First it depends on where you live and where you are gonna hunt. I use 12, 20, and .22 for small game just depends on where I'm hunting and what I feel like shooting. .22 is a little more challenging so I use it a lot but if I'm hunting near some houses ill use shotgun to avoid any possible extra bullet travel. If you want to move up in game choice I would get a 12 that way you can a little heavier gun for the bigger game but a 20 would work just as fine. As far as starting get your safety course done get your license. Walk into the woods look for some squirrel nests and sit next to a tree. Clear out the leaves underneath to avoid a lot of sound if you have to move around to get a better shot and wait. The squirrels will be coming in the evening to nest and catch em on the way in. If you get one down go pick him up, come back and sit down and wait. They will move again in about 10 min