Any tips or strategies for mania and survival mode?

I'm having a hard time beating the game on mania difficulty and getting higher ranks on survival mode. I use SOR2 Axel and SOR3 Blaze by the way.

Using Axel is part of the problem...he's one of the worst to play mania with, unless you know how to handle him. I did write this guide after making an effort to learn him more, hopefully it'll help a bit. Blaze is only average as well (especially with 3's low damage output) but is somewhat better at crowd control. (throws and fly-kicks are king)

But in general it's about learning how the mobs move, as well as tricking them into doing stuff. Also note that weapons are less effective in general (because the mobs are faster), food can't be left around (they will grab it at the first opportunity) and be wary of mobs with long-range attacks when they're off-screen. (it's total BS but they will use them and hit you with no chance to respond)

There are general tactics you should always employ:

1.) Abuse invincibility through throws, specials, and any other options in a character's arsenal
2.) Kiting. Emphasizing what DarkThief said, knowing how the baddies behave is crucial to be able to kite efficiently. This plays into manipulation, which is the greatest asset you have for both defense and offense. In my opinion, studying your enemy is best done in Survival and Boss Rush modes.
3.) Kick them when they're down. Mania AI is cheap as hell so don't hesitate to grapple spam a specific enemy.

Axel is definitely a difficult character to be successful with. I'd suggest watching the survival videos I've linked in my Survival thread to see optimal tactics that players employ, first-hand. There's no hardcore survival runs with Axel that I know of, unfortunately. In the end, if you want to get better, practice, practice, practice.

Good Axel mania run:
https://www.youtube.com/watch?v=HS0lAbOWg7s

Survival mode is very difficult, good throw is the secret of success