"Once per turn, you can select any number of face-up Spell or Trap Cards. Return those cards to their owners' hands, and distribute new A-Counters among monsters on the field equal to the number of cards returned. Once per turn, you can remove 2 A-Counters from anywhere on the field to destroy 1 card your opponent controls."
A quick look at it, and it doesn't seem to help you get any field advantage, since the only cards you can bounce are face up spells and traps. While Gol'gar does get rid of certain traps, continuous/equip/swordsofrevealinglightkindof spells, and field spells temporarily, there's no guarantee that a deck you're going up against will use one of the above. That's when your deck comes into play. For example, you can stock your deck full of stall cards such as Swords of Revealing Light or Nightmare's Steelcage, and simply bounce them back to your hand, attack, then replay them, while also getting nifty A-counters to use to wreak some havoc on your opponent's field! Here's some cards to go with Gol'gar. Also helps stall the duel anyways till you can get a Gol'gar out:
Swords of Revealing Light
Swords of Concealing Light
The Dark Door
Level Limit Area B
Level Limit Area A
basically any stall card
Also, Gol'gar give you the potential of reusing cards such as Limit Reverse, Call of the Haunted, and Different Dimension Gate, which, otherwise, has a one-time-only use. But with Gol'gar, after you synch the resurrected monster (assuming that is wat you do, or tribute it), you can bounce that card back to your hand for another use!!! AND, in the meantime, you get even more a-counters to use to blow up your opponent's field.
aaand yeah, that's all I can think of right now about Gol'gar.