Since it is hard to hook gars, most gar fishermen use large circle hooks attached to a steel leader as a rig.
The leader is connected to the main line with a bobber attached above the leader. Line strength depends on your own preference, but remember it is quite possible that you will be tangling with a fish that weighs over 100 pounds and possibly double that! They aren't line shy so don't let that worry you. A typical all around gar fishing rig consists of a 40 lb main line tied to a barrel swivel. A 2-3' length of wire leader is then tied to the other end of the swivel with a haywire twist.
To complete the rig, use another haywire twist to tie a medium sized circle hook on the tag end of the steel leader. Put your hook through the bait only once. Hiding your hook is not a priority since gars tend to be found in murky, slow moving waters.
For bait, use a whole mullet that has been scaled. This makes it much easier for the gar to swallow the bait. Hook the mullet through the back just behind the dorsal fin or in the lips. For smaller sized gar, use chunks of mullet instead.
Gar like to swim away from the other fish once it has its prey secured so that it may eat without being bothered by other gar. It is important to let the fish take your bait and swallow it before setting the hook. When the bobber takes off, follow it until it stops. This is the fish positioning it to swallow. When the fish starts to move off again you should not try to set the hook so you don't pull the hook out. Instead, begin reeling in the slack until you come tight and hold on for the fight.
Be sure to carry a dehooker with you so that the release of the fish is safe for both you and the fish. If you can't reach the hook, cut the leader as close to the hook as possible so the hook may fall out on its own.