My friend introduced me to this game about a year ago and I got hooked instantly, even eventually going as far as to buy a 360 pretty much to play this game.
When I started playing, I mained Rachel, and her most basic bnb of 6a, 5b, j.b, j.c, j.b, j.c stumped me until someone broke it down on the forums here.
I feel that its way easier to learn if you can visualize exactly what your character is doing/going to do. But also if you understand why they do it.
I would never have figured out Rachel's bnb combo if someone didn't break everything down to its most basic notion of "6a is a launcher, 5b keeps them afloat, hit jump then hit b, then c, then jump again and repeat"
That combo took me about an hour to learn, and then 3 more to burn it in.
You have to think of a combo as a 3 course meal, daunting to cook at first, but when you break it down and figure out what you're doing, you stop being flustered at how complex it is.