Advice going to PBEM

[Inishfree]

I'm working my way through the DLCs. I'm about 1/2 through. I am on FM level and I was doing pretty well...maybe close to ready to jump to GM next time through. I tried PBEM for the 1st time. I am getting totally destroyed...like not even close.

Any advice to speed up the learning curve making the jump to playing other players? I can't see what exactly I'm doing wrong. Following the normal basics as much as possible (units in the right terrain, backing up with support when possible).

I expected to get beat a lot in the beginning, but I don't feel like I am even putting up a reasonable fight.