Sakura: Learn her cross up combo (cross up forward, low short x2, stand short, fierce dp - note this can be expanded upon, but just learn this version first). Get good at reading when crossup will connect and when it will be blocked then go for mixups involving her throw, which puts you back in crossup range. The way I play A2 in general is to never have more than 1 meter, if you have level 2 or level 3 - you had best be saving that shit to go through a fireball or something ‘big’ because you are losing wayyyy too many opportunities to be landing level 1 cc or kick alpha counter. Her standing roundhouse is hella good - just pressure, go for crossups and if you see them whiff something, custom them back.
Chun: need to be super boring and super robotic because the bitch is too good in the game. Just learn low forward fireball or low forward flip kick then look for opportunities to land her level 1 cc since it does like 40% damage.
In General: Get good at low blocking and doing alpha counters - a very important skill to know in A2.
Even though it’s 900 years old - the B3 video has good chun footage on it. Forget if there is Sak footage - but if not - here is a random vid of choi vs valle, with choi playing sakua: [media=youtube]c5nf_wY9kWk[/media]