That's a good question! Here's our tactic for domestic games:
For European games against better teams than us, we switch the mentality to Very Defensive. That sets us out to be stable at the back, and when we get the ball we move it incredibly slowly and with short passes so we don't waste possession. A lot of our European games have about 5 shots each, which is absolutely perfect for us. If we try and play an open, expansive game, we're going to get battered Normally I think possession just for possession sake is one of the biggest fallacies in football (see Spain against Russia in the World Cup), but my philosophy with this is that we have much weaker players than the opposition do, and so the longer we have the ball, the less time they have to create chances against us. Often what happens, too, is the big teams expect to be able to dominate us and so get fed up of us passing the ball around the back for 90 minutes, so start to play really high up - which is when we can ping one over the top for the 17 acceleration of Claudio Fabbri (YP32) to sprint onto and set us up on a dangerous counter attack
Most of our goals - okay, maybe not most, but a large proportion of them - come from set pieces, too. Set Pieces is an area I'm incredibly passionate about in real life (you have to be as a Rotherham fan!) and I think it's a really underdeveloped source of goals - especially as a technically inferior team that has a physical advantage, like we often do. I've tweaked our corner routine a lot until I've found one that I'm happy with, I've come up with a long throw routine that tries to avoid the weird quirks in the match engine with long throws this year while still being effective, and we score quite a fair few from free kicks, too - the goal that Davide Toccaceli (YP19) scored to win us our Europa League group was a header from a free kick, and Claudio Fabbri (YP32) absolutely tonks in a few direct ones every year too.
Oh, and if we're away, I'll usually turn timewasting up to 'whenever possible' too. It's not pretty - it explains why in 180 minutes of football with Zenit we drew 0-0 - but it's effective