The only thing I've learned (At least for me) is that spending hours in traning mode isn't the way to go.
Don't get me wrong, training mode is great, but I found that I spent hours trying to figure out how to do a few combos in training, and then couldn't actually pull them off in a real match.
Basically my strategy is to learn normals/command normals first: Combos are essential, but if you don't know the properties of the moves that you are using in said combos then you're at a disadvantage. Try a few fights relaying only on normals and very basic combos against the A.I
Next I focus on Special moves, this step might not take quite as long, but I still think it's better to learn the nuts and bolts of your big damage combos before actually putting the pieces together.
After that, BnB's making sure to practice execution and memorization, since I'm pretty horrible at this step, I'll work on one BnB for a while, then take it into an A.I fight and try to keep it consistent.
After the BnB's learn more advance combos, etc.
Watch videos of people playing high level matches while doing this, focusing less on the overall action and more on specific things that your character does that is effective.
Be patient, as I'm starting to learn, this game isn't like SSF4, if I'm anything like a normal player, it takes a long time to get good.
Emphasis on a long time.
As this is my second post, feel free to flame me for being wrong.