General Tactics
Jump/Super Jump back and J. Hp.png or Lp.png Viper Beam. If you normal jump, you can call assists to aid your zoning ability. Throw Tiger Knee grenades (D.png, Db.png, B.png, Ub.png + Lk.png or Hk.png) to stave off approaches and control space. Block often. Wait for your opponent to make a mistake, then Tiger Knee AHVB to punish. Be sure to land multiple loops of it to maximize the damage out of any scenario.
Team positioning
The mere sight of a five-stock Cable is enough to make even the most advanced players break into a sweat, so a classic tactic is running a strong battery like Storm or Spiral then bringing in Cable. His assists are also decent, but he likes having an assist himself for mixups and defense since he struggles in those areas somewhat.
Point
Cable is strictly OK on point. Being able to launch into AHVB at any point after the round starts is nice, but you'll only be able to do one until you build another bar (which makes AHVB mostly usless aside from a one-time, high-damage punish).
Mid
Probably his best position