Baiken is a nice character to use. Just learn how to do her counters and sit there all day blocking. You don't ever need any overdrives, but if you wish to have some, go ahead and start attacking. Baiken is alright to use for a newbie, but it's not recommended.

Moves List

Tatami Gaeshi - QCF+K (OK in air)
Zakuro - (while guarding) QCB+P
Mawarikomi - (while guarding) QCB+K
Sakura - (while guarding) QCB+S
Suzuran - HCB+K (This is a dash forward that blocks everything.)
Yozansen - (in air) DPM+S

Overdrive Attacks

Sanzu Watashi - QCFx2+S
Baku KI - (while guarding) HCB+P (Effect - Unknown for now. I just can't remember if it disables jumps or overdrives.) (The Instructions Booklet says that the motion is B,HCB+P, but since you're already holding back, just do the HCB+P, it still works.)
Baku RIN - (while guarding) HCB+K (Effect - Unknown for now.I just can't remember if it disables jumps or overdrives.) (The Instructions Booklet says that the motion is B,HCB+K, but since you're already holding back, just do the HCB+K, it still works.)
Baku RYU - (while guarding) HCB+S (Effect - Unknown.) (The Instructions Booklet says that the motion is B,HCB+S, but since you're already holding back, just do the HCB+S, it still works.)
Baku HOU - (while guarding) HCB+HS (Effect - Unknown.) (The Instructions Booklet says that the motion is B,HCB+HS, but since you're already holding back, just do the HCB+HS, it still works.)

Instant Kill

Press All 4 Buttons to activate the "Attack Mode" then while in it:
Garyotensei - QCFx2+HS

Combos

K, S, HS, QCF+K
This is a basic combo. Follow what it says and you have a nice 4 hit combo right there.

Guilty Gear Mode Changes

She now has two new moves.The first is RDPM+P. It does her Zakuro, only without having to block first. The second is QCF+HS. This does her Tatami Gaeshi, only three come up instead in a wave. It just has a slightly longer activation time.
Also, her air and ducking Slashes seems to have changed.

Gold Form Changes

Not much. She's the same as the Guilty Gear Mode Baiken only with increased stats.