Pasted from my post in the Using Jam! thread...
5K is a 5-frame low that gives +2 frame advantage on hit and is an important part of her ground strings and frame traps.
I'm not in the position to do an in-depth overview of Jam's movelist since I'm still learning her myself, but here's some stuff that you HAVE to use.
2P - very fast move that gives awesome frames for frame traps, and is also an important part of Jam's gatlings.
2S - staggers on CH, good priority, nice hitbox, and neutral on block
2D - knockdown, jump cancellable for very good okizeme mix-ups.
f.S - good far poke that hits high and is jump cancellable. Good airdash starter and combos into TK Ryuujin for awesome abare. Good anti-air against some characters with not-so-good jump-ins like Millia without pin, but will never work against Faust's j.D or Slayer's j.H.
6K- makes crouching characters stand up on hit. Insert this into a gatling if you want a crouching character to get hit by Ryuujin. Jump cancellable too.
j.P - good spam tool when airdashing and anti-airthrow. Good pressure and mix-ups if you vary the number of j.P before landing.
j.S - anti-air and air combo staple. JCable in air.
j.HS - good priority air move and hits behind her for cross-ups. Nice CH stun against airborne opponents for re-jump combos.
j.D - good whiff punisher when used in conjunction with IAD. Prone to IB punishment unless you add in a j.2K after j.D gets blocked. Leads to a free combo for Jam on hit.
I think those are her best normals. It's good to learn all her most useful gatlings, especially those that give frame advantage on block. And unless you want to gatling into 3 kicks, end the gatling in a 2D for a free power-up or okizeme mix-up afterwards.
Burst Cancel - parry something, use your Burst and IMMEDIATELY cancel it with faultless defense. You retain your Burst invincibility but you're free to do whatever you want.
I'm at a loss as to which of Jam's combos are considered B&B, since I'm normally pretty freestyle with my combos. But generally, long-ish ground strings with a few 2Ps and 5Ks should be ended with a 2D + charge/oki mix-up...
heavily prorated ground string~> 2D, charge
any ground string~> c.S, f.S, TK Ryuujin, RC, j.S, JC, dj.S, dj.H, 3Kicks (works on all characters Millia height or taller, except Faust)
any ground string~> 2D, TK Ryuujin, RC, j.S, JC, dj.S, dj.H, 3Kicks (works on Millia, May, and Zappa)
Throw FRC~> c.S, f.S, SJI, sj.S, sj.P, sj.S, JC, dsj.S, dsj.HS 3Kicks
Jam has a very open-ended combo system, but those are the basics. Big combos involving CH 236S~S and IAD 214K are very spacing dependent, so I'll leave those for the pros to explain.
Now for a question of my own. What're the character specific ground string enders for Faust and Baiken? For Faust I've been settling for 2D JC j.K j.D 3Kicks. For Baiken, I do 2D RC 5K f.S air combo which I think is a bit of a waste of tension. Recommendations?