Lush i have found is useful for many things, according to the book "Enemies cannot build on lush". This means that god powers like Tartarian gate and underworld passage cannot be placed in it so it is sort of like a down graded version of the Isis monuement power.

There are two rules for using lush
1.Buildings should be spaced as to get the largest effect area
2.It can be used to secure gold mines and possibly settlements.

The main strategy for using no.2 is to build manors, guilds and later towers near your or your opponent's base to take valuable gold mines and settlements.

Also something I would like to include into this is a bonus guide to the fact Gaia's buildings regenerate. This also means two things that should always be known and used
1.This can save you resources and as long as the enemy does not attack in mass you do not have to repair your buildings
2.A very good use for this is the tartarian gate.Also it is a possibility that titan gates can raise their hp by their selves.(did not test that yet)

I hope this double guide helps those who use Gaia and yes Pug I tried to be more thorough so if anybody could suggest something do it and i will gladly add it

Enjoy!