This thread gets made every two weeks, so I'll save you guys the trouble and make one for you.
Guilty Gear button Layout (for XX, #R, Slash, and AC)
= punch, = kick, = slash, = heavy slash, = dust, = nothing
BlazBlue button layout
= A, = B, etc, = nothing
In the arcades, you pick either one of the configurations before you pick your character. In CS there is also an easy mode option, but no one who plays seriously uses it.
Persona button layout:
for all games, the taunt/respect doesn't have a real defined location, since it varies depending on what type of arcade cabinet you play on. So people who play on consoles with an arcade stick just put taunt/respect anywhere or don't even assign it to a button if they know they don't ever want to press it on accident.
1. go into training mode and practice combos, setups, moving around (running, instant air dashing, super jumping, etc)
2. if you're having problems doing certain things (like say performing a motion), then set training mode to show your inputs (trust me it's there) and look at what you're doing wrong. Then practice doing the motion correctly.
3. PRACTICE. PLAY OTHER PEOPLE. DON'T GIVE UP
Buying a Joystick:
shoryuken.com also has a lot of resources involving stick buying/building/modding.
Holding a Joystick:
this isn't an definitive guide, it just shows some common ways people hold joysticks. Find (or develop) a way to grip the joystick that's comfortable and usable for you.