Really improve TG ELO by 1vs1 practice?

Hey folks,

I have the following problem: we have a small community of colleagues (8), who plays regularly 2/3/4 vs x/x/x with very different ELOs ranking from 800 to 1500. We do play as random teams mostly and I really do want to improve. (Dunno why I'm always on the losing team). My 1vs1 ELO is not too bad around 1100, and only one opponent I can focus on is always ok for me but in TGs I totally mess up. So the question is how do I improve especially in team games? Like play more 1vs1? (can't imagine) Play more TGs with randoms? (had rather bad experiences).

I just don't see the path right now how to get better in in TGs of a semi skilled, regularly playing together group of ppl. I mean, they even choose the same civs and build orders all the time and it seems it's only me who fucks TGs up at a regular basis.