General gameplay tactics and its features.

Hello everyone! I really want to learn how to play at a 200% rating. I play on random XL maps without water, and since the units on the map are strong, I end up with a lot of resources, but the problem is that some of the bots (Necromancers, Elementals, Swamp creatures) reach me quickly and destroy me. Please give me a very effective tactic for playing as Swamp (I really love this faction and always play as it).