What insanity said, with some moderation
Train your players into "away" tactics, and use it almost regardless of the oposition. Preferably counter tactics, if you have a deep lying playmaker/good passer of the ball and one, two or three really fast players. If you have a fast striker, make him target man with the 'run onto ball' option.
I always train my team in three formations/tactics. One controlling/attacking, one 'regular' and one defensive/counter. But in all tactics I use the counter-attack option. As long as you make sure to have fast strikers and/or wingers/wide midfielders, counter attacking is
always useful. Especially in lower leagues, pace is everything. Even without good finishing skills, two really fast players can make the difference, especially away from home. (It is of course good to have good tacklers in defense, who stays on their feet when tackling. This can be trained though)
It is important to stick with formations/tactics. It is no use in training formations/tactics every day, if you constantly change them on match day/during a match. To get the best out of tactics training, keep them quite similar. To explain: I train my team in three formations/tactics and change positions (ex: use an AMC in attacking/controlling, a DMC in defensive/counter, change wide mids for wingers, etc) and mentality. But I keep the same marking settings, pressure settings, and almost the same tempo and width settings.
This way, players get to know the style of play very well. I guess players on FM are quite simple people
, so using one formation with man-marking and slow tempo, and one with zonal marking and very high tempo, just confuses them...