I think the engine is a bit more sophisticated than some players give it credit for. I've been playing on and off for a couple of years, with a couple of teams that I've kept going for 5+ seasons. One team I got promoted first season, then had a couple of seasons in the top half winning a cup or 2, and then won the league 3 times in a row. That's in a league with 20-25 players, so not as competitive as the RAWK league. The other long term team has been 1st or 2nd every year, again in a 20+ team league.
I think the engine is basically a more complicated version of rock-paper-scissors. Certain formations and tactics work better against others. There are also some game stats that are more important than others, so working out which stats you want to try to maximise should help. The larger the gap in average rating the less tactics matter, but I've stilll found that certain formations do well against higher ranked teams. Add to this morale, fitness, preferred positions etc.
Having said all that, I've never been in a league where so many decent players are already taken, so I'm expecting this is going to be a lot tougher. Personally I wish the game limited squad sizes to around 50. I've realised that in the RAWK league money counts for nothing as hoarding players is a tactic, and chairmen won't allow bids high enough to be tempting.