As for help... here's my terrain design guide...

Terrain

Trees:
The key to making good terrain lies in trees! Trees are perhaps the greatest difference in terrain between AoE/AoK and StarCraft. They look quite good and can control a player's actions in the scenario. However, I have found from experience that to restrict player mobility (even if it is neccessary for tactical difficulties, storyline, etc.) can result in problems. Thus, to control player movement and still allow for mobility, place roads where you want the player to go. They are useful as well as realistic and attractive.
Around the roads place the woods. Mix various tree types but be realistic! Don't put palms with pines and so on! I barely suggest mixing pines with decidious trees (oaks). Cover the area below the trees with flowers, rocks, gaia stones, forage bushes, and animal life. Be sure to space trees well so that you have space for these accessories. (the roads will restrict the player)

Water:
Now comes the next great terrain feature: water. It is perhaps the most restrictive and forces a player to use a boat or a bridge to cross. Being plain and not animated, it may seem dull. Nevertheless, there are many ways to 'spice-up' water, if you will.
But first, one must differentiate among the various types of water. Not the water1, water2, and so on, but rather the sizes of the water you will place on the map. These include rivers, streams, lakes, and oceans.
Streams-
When making a stream remember that these bodies of water are very narrow and can not be manuevered by boats. It looks quite ridiculous seeing a small river with ships on it that compose 1/2 of the width.
Along the shore-line make shallows at good-sized intervals. Place a few rocks along the shores, too, to cover up that large beach that appears when you put down those shallows. Put shallows down for the crossing. Don't use anything else!
Rivers-
Rivers are larger streams. The water, like streams, composes mainly of water1, but in the center of the widest areas, there are narrow areas of water3 (the middle depth). Shallows are rarer along the edges but exist nonetheless. Make crossings with bridges but avoid use of ships. One or two fishing boats are fine, but don't have galleons patrolling the waters! Similairily, don't have docks. They are just too large.
Lakes and Oceans-
Lakes and oceans are basically the same. The water composes mainly of water3 with water1 along the shores. Well into the body of water, place some water2. A few flecks of water1 even in the deepest parts do well to appear as waves. Place a few islands and you have a beautiful ocean or lake.

Grass:

Grass may seem to be the all-around, multi-purpose terrain, which it is. But when you look at the terrain box in the editor, you'll notice three different grases. These may not seem too different, but, in reality, they are. One grass is the standard, that which you always encountre on a blank map. The other two are slighty different, one more green and lush (use this for jungles and what not), the other lighter and more worn down (use this grass for the grass at settlements). Below are the three grasses (in order of grass1, grass2, and grass3) as well as the two dirt-grass hybrids (in order of dirt2 and dirt3):

Cliffs:

Not exactly a terrain, I don't particularily like cliffs. They look bland and brown, the original greyish AoK beta cliffs perhaps far better. Personally, I can't say much about cliffs, as I never use them.

Mountains:

Also not exactly a terrain, the mountains in AoK did have better versions in the beta. The mountains included in the final product resemble more tropical mountains, meaning they look best surrounded by palms and what not. Because you'll have a good deal of difficulty placing them, it is best to copy a mountain then paste it wherever you want (including near other mountains to form a range). Just be careful to not place the mountain too close to the edge of the map lest the game crashes.

Desert:
Frankly, I don't particularily like the desert tileset in AoK. If you examine a few tiles of it, the desert terrain seems well-detailed with what appear to be ridges and grooves in the sand. Set down several dozen tiles and you quickly see the problem, however. The well-detailedness of each individual tile lends a uniform ugliness to every tile in a large desert.
I suggest avoiding use of deserts. They are, to be blunt, ugly.

Hills:
Hills aren't very restrictive but can lend a nice tactical touch to a scenario, forcing a player to concentrate a battle at the hills. They can look quite nice as well. Traveling with a small band of soldiers through valleys of well-treed hills can look quite nice.
Hills in AoE were nothing compared to those in AoK. Many AoE designers choose not to have too many hills as their steps seemed almost ugly. AoK's smooth hills are a vast improvement, but they can cause some disorientation to a player (as the height of the hill can not be judged by the number of steps). Don't worry about this, though.
I personally prefer higher hills. The taller the better. When making them, hold the mouse down and move gingerly about in nice curves. This creates some nice valleys. Now and then, let go of the mouse button and move an inch and make another hill. After this, move down to a lower hill elevation and do some of this area over.
Now, beautifying hills is the hard part. Too many trees can seem unrealistic and placing flowers and filling the ground can ruin the depth and heights the hills are meant for. There doesn't seem to be an effective cure for this so I shall not speculate and I wouldn't want to state a guess....

Eye-Candy
No matter how great your idea for a campaign is; no matter how complicated the triggers are; no matter how much strategy is involved, your campaign will be sneered upon if it lacks that which is appealing to the player's eyes. These objects which can help your scenario greatly are usually refered to as "Eye-Candy".

Ambient Life
The world we live in is not composed of wide, empty tracts of land. Rather, there is great variety. Much realism can be granted to your scenarios with the addition of ambient life.
In AoK, ambient life composes of everything from flowers to rocks, from deer to forage bushes.

True Areas of the EarthNow that I have briefly discussed the basic terrain types, I can now make note of the different areas of the earth and how to represent them in a scenario. First, I shall start with the sweltering deserts of Arabia and Egypt:

Deserts-
The Desert terrain in AoK looks rather bland. For effective deserts, put down a lot of dirt (i forgot the exact number) and then do some of that area over with desert. It may not look great, but its an improvement over the plain sands. Now and then, put a stray palm tree. This will beautify the area a bit and will due good for the psychological effect of a scenario. If the scenario has something to do with being alone in a desert, for example, having the player pass by a lone tree will probably heighten this effect.
Anyway, now and then put some hills in the desert. This will form sand dunes.
Your desert may seem plain and boring but that's what they were! However, for practical purposes and because they exist in real life, you would be good to throw in some oasi.
Chose a spot where an oasis is practical and put down some water1 (it is bright and clear and contrasts well with the dreariness of the surrounding desert). Around it set down some palm trees and for a radius of some tiles, put down scattered trees (one or two heaps and a dozen or so scattered trees would do). back at the oasis, put down a little grass and some fish. In AoE, alligators, lions, and gazelle fit well in the oasi, but those don't exist in AoK. Thus, don't bother putting down much wildlife.
You may want, for storyline purposes, to put down a small settlement. Use the Middle-East building set (in the feudal age preferably) and make a few houses with maybe a stable (after all, they can't stay in the desert forever). If you chose to do this, make more grass than you would've if you didn't have any settlement.

The Central Asian Steppes-
From Central Asia, the horsemen came. First the Cimmerians and Scythians, then the Huns, then the Avars and Alans, then the Turks, and finally the Mongols. They were a place of dry plains with a few hills and cliffs now and then. Basically, they were boring. However, you may take artistic liscense when depicting them.
Start out with placing dirt and that dirt/grass combination (i dont recall the type and numbre). Now and then, make small hills (hill3 would do well) and a few cliffs, if you like. You may now begin to take artistic liscense....
Place rivers. These can change the climate of the scenario substantially. And they actually did exist in the western-most regions of the steppes (ie- the rivers Volga, Dnieper, etc).
However, here comes the difficulty: Vegetation.
I haven't the slightest idea what the vegetation of the Steppes is like. Grasses are rare so trees must be even rarer. I suppose temperate trees (forest and oak) would be the best, though I am not sure. When placing them, space them well. Sadly, you can not put grasses or anything else for, by doing so, you are turning the map from Central Asia into Europe and Mesoptamia.
Now, when you have a boring looking map (as you will have now), normally you would make great cities but these don't exist in the Steppes. Making this region is very difficult as it does not lend much to the eye. I would like to see someone try at it, but I doubt it's possible to make a truly good, yet realistic, Steppes.

Europe-
European terrain is probably the most common terrain used in scenarios and campaigns, largely because it is the easiest to make. The Europe-style map composes of grass with woods of pine and oak. There isn't much else to say as it is always seen and quite simple to make. Furthermore, with a few alterations (chiefly the addition of bamboo), your map can become rather Asian.

Final Word:

The above was only a mere examination of a very small area of map design. It did not encompass story-writing and telling, trigger usage, AI files, and strategic works, but did a rather crucial aspect of a scenario, that which the player encountres first: the terrain. Thank you.

Thanks