If you decide to do home cooking, get a dog food supplement that contains all the necessary vitamins and minerals. There's lots of them.
Some people prepare raw diets, that fresh venison meat, is great, I would feed it raw un-cooked (if your dog accepts it) and supplement it. There's a lot of charts out there about preparing balanced raw diets.
For kibble, get rid of the beneful, here's a good chart explaining why beneful isn't the best choice.
Beneful Chart
If you want to try a sample pack of all different Kibble, where you get somewhere over 20 different samples of good quality kibble from various manufacturers and a few extra things. It's a nice package.
Luke's All Natural Pet food Sample Pack