hi there. im on man city too. well im not going to offer you any tactic as i havent found the winning one for myself yet. but i still can give you some advices.
first of all dont even think of losing Petrov, hes amazing winger who lead in assists every season for me.
second you should take a lot of attention of training Nedum Onuoha. at the very beggining he has 14 of each tackling jumping and heading. if you raise these stats to 16 at least your central defence (richars and anuoha) will be unbreakable. also once you did this you can set "play offside" options as richards and onuoha are very fast.
if there is AMC in your tactic, sign Arshavin. hes very good, always lead of average ratting for me. if you have no AMC position in your tactic, still buy Arshavin
you can train him and set new position AMR, hes doing great there too!
sell Robinho! this kid always wants to move to bigger club and his claims just damaging team's morale. you can get over 60 millions for him.
well i think its all for now. keep updating me mate about your Man City run (H)