Introduction
Gameplay Overview
Mai is a very solid zoning/poking/runaway-based character. Her fast but higher than average jump and air dive lets her control the air a bit different from most characters. Her Ryuu Enbu, along with her Fan Toss and pokes allow her to zone and keep advantage on the ground quite effectively. While she falls mid to low-mid on most tier lists, it is misleading because she doesn't suffer matchups vs the top tier as bad as a lot of other characters that are usually ranked above her. She requires good execution/reflexes for hit-checking cr.C, but aside from that she is pretty average on execution. A good character for a beginner.
Combos
Mai only has a few combos, let's check 'em out.
cr.C/cl.C xx Ryuu Enbu (qcb+P)
cr.C xx Ryuu Enbu (qcb+P)/Killing Ninja Strike (hcf+K)/Super Killing Ninja Strike (qcb,hcf+K)
cr.B,cl.A xx C Ryuu Enbu (qcb+C)/B Killing Ninja Strike (hcf+B)/Super Killing Ninja Strike (qcb,hcf+K)
f+B, cr.C xx Ryuu Enbu (qcb+P)/Killing Ninja Strike (hcf+K)/Super Killing Ninja Strike (qcb,hcf+K)
[corner only, meaty] A Ryuu Enbu (qcb+A), st.A/B
[corner only, meaty] A Ryuu Enbu (qcb+A), cr.C xx Ryuu Enbu (qcb+P)/Killing Ninja Strike (hcf+K)/Super Killing Ninja Strike (qcb,hcf+K)
[corner only, meaty] A Ryuu Enbu (qcb+A), B Killing Ninja Strike (hcf+B)/Super Killing Ninja Strike (qcb,hcf+K)
Note that cr.C is hit-confirmable, so never do hcf+K or qcb,hcf+K on block obviously. For the cr.B combo, input cr.B, qcb+A, hcf+K for the super input.
In-depth analysis
Normal Throws
b or f+C - Breakable, forward knockdown, face forward, rollable.
b or f+D - Breakable, reverse knockdown, back turned, un-rollable.
Normal Moves
Standing A - Nice fast poke, just a little short-ranged. Good followup after a meaty qcb+A in the corner.
Standing B - Fast, great as a short hop anti-air. Whiffs on crouchers, but the recovery is quick.
Close A - Her best cancelable light attack (only other is cl.B and it sucks).
Close C - Good anti-air when they are at a close/high angle. Fast, cancelable.
Close D - Kind of like close C, but it doesn't activate from as far, so stick with close C.
Crouching B - It's very slow and crappy for a cr.B, but it's her only combo-able low attack.
Crouching C - The main combo/meaty normal. Lots of time to hit-confirm into hcf+K or qcb,hcf+K off a normal hit, if it's meaty if course you'll have less time depending on how early you do it.
Crouching D - Sweep, pretty meaty but otherwise insignificant. Not cancelable.
Jumping A - Cancelable.
Jumping B - Very nice hitbox/high priority, can cross-up.
Jumping C - Fast, actually pretty good for air-to-air or as a jump-in. Like Chizuru's jumping C, it has less hit-freeze than most jump attacks, so you have to perform your ground followup from a jump-in very quickly. Cancelable.
Jumping D - Nice long-range jump-in, pretty fast too. Usually the jump-in of choice, and good jumping back air-to-air. Cancelable.
Jumping CD - Not bad, though the hitbox leaves a bit to be desired for a CD in my opinion. I think it's her jump speed/angle that makes it not as good as it could be. Still, there it is, and it's cancelable.
Command Normals
f+B - Slow overhead, causes enough hitstun to combo a cr.C afterward. Advantage on block. When chained, is still really slow and not overhead, and cancelable (into air qcb+P). You can slow cancel it, but remember it's REALLY slow. Can be used as a meaty.
d/f+B - Combos from any chainable attack, but it has really bad recovery. You can go under the highest fireballs with it (O.Ryo/O.Robert/O.Yuri/Takuma).
Jumping d+A - More hitstun/blockstun than a normal jumping attack, like Kyo's jumping d+C. Cancelable, slams on an air-to-air hit. Can crossup if you hit them right on the head.