It's been a while since I played a lot, so my advice will not be perfect, oh well.
When my opponent is around mid-screen and farther away I like to use 214A, it's a great spacing tool but you can get hit out easily if they are close, 5B, 2B, and 6D are better when they are close. I like to use j.B and sometimes j.A while in the air, the j.D moves can be good as well. 214B is good for anyone trying to stay fullscreen away from you, but don't use it too often
It's mostly frametraps when I try to open them up, so I will use Ignis a lot. You can try for an unblockable set up with either 236D and an overhead or 214D and a low, but I only really go for those in the corner and they can be avoided easily. 214C can be a great tool as well and if you manage to start a combo with it you will get great damage. 6A is your only standing overhead and is pretty slow, use it with Ignis imo. 3C is a sweep that is jump cancelable on block.
Defensively, 2C has head invul and will FC, so it can be a good AA but it can also be hard to hit with it, 6B can also work as an AA but is not as good. All his supers can be used as reversals, 632146C/D and his Astral have in invincibility frames, 236236D will trade but Ignis will keep going making it favorable for you. There is also his dodge, 236A, which is not that great on it's own, but if Ignis is out then you can use any D normal at the same time, 6D is the best. being on the defensive without Ignis or meter is tough for Relius.
That's all I can think of right now.
Edit: here are everyones extra colors and some other stuff.
http://www.dustloop.com/forums/showthread.php?15448-BBCP-Arcade-Profile-Site-Rip
Azrael's Kamina color...
Welp, new sub.
Oh, and Bang has a Goku color.
I like CP's palettes.