The best advice I can give is to use EA to raid easy Gunpowder bases and build up your troops then buildings (maybe even walls) for the jump to Industrial. EA bases don't have much oil and if you want to raid IA bases you'll need strong troops. You should prioritise raiding over protecting but you can also use this time wisely and experiment with base design.
In EA, loot is easy to come by but the jump to IA is 2 or 3 steps up in time and difficulty so think of EA as a stepping stone for when the real action begins: Industrial!
ps: multiple compartments or sections is a good start, to confuse the attacker.