Something I have tried with Antelope (sage grass taste can be strong) is soaking it in tomato juice. The acid in it tenderizes the meat and kills any other taste. Rinse it off and prepare it just like beef.
A lot of times when I go backpacking I' ll pack a couple of deer steaks in a zip lock bag in soy sauce. It doesn' t take much, just about a 1/4 cup in a bag with two small steaks. It help preserve them for the day hike in and when I grill them they taste great. Both simple but they work.