-I play the song repeatedly, if that doesn't work...
-I turn on the autopilot mod to see what I'm doing wrong (helps if I don't understand the rhythm or if there are complex patterns) If that still doesn't help...
-Play the one part I keep failing/losing combo on repeatedly in the editor. If that fails...
- Half time! Trololol. seriously though, it's good preparation for the real thing. I can understand the rhythms and read the patterns a lot more easier on halftime, after that it's simply a matter of being able to do it a bit faster
If that doesn't work...
-All the above things...on halftime. And if THAT doesn't work...
-Give up, lol.