It's about more than just good players and a good formation. A big part of becoming successful in the game, just as in real life, is getting the players to like each other, work well together, getting them motivated, having flexible tactics, considering the opposition, etc. For the flexible tactics, my article
could help. For the other things, it's just about how you approach the game really.
You often see people asking for a tactic to fix the problems they're having, when the real problem isn't actually their tactics. It's hard to work out what might be going wrong for you without more info, I hope you get it all worked out, if not then I'm happy to help!