Yeah its possible. The following isnt bragging but just illustating my point:
I got AFC Wimbledon from the Conf South to the championship winning the Carling Cup on the way. I just plugged away twiddling with my own tactics when they seemed to need it, trying home/away tactics saving/altering them over time.
So, success. The problem unfortunatley is is that I dont understand why I have been successful, I dont know what I did that won games. Was it the players? Was it luck? was it my tactical genius? (no!).
It was pleasing to get promotions under my own steam but baffling as I dont know why.
I didnt come on this forum at all til recently when I got promoted into the premiership, I too have started using all the different approaches and tactics because I was daunted managing in the
prem without a clue how I got there. None of them have worked for me for more than a few months and I am again lost wondering what to do.
I am at the point where Im deleting all the tactics Ive downloaded and trying again blindly fumbling in the dark.
My previous career mirrored this pretty much exactly. I eventually got to the point where I won the champions league and the world cup, dunno how. I recently tried the Home/Away tactic that won trophies in my previous game. For my current AFC game was as useless as others Ive tried.
My only suggestion is stop downloading tactics and try to develop your own over time. It'll eventually work but I'll be buggered if I know why.