You don't need a gym to workout, but it helps. You do need to eat right, and cardio MUST be involved in your workout. Depending on your current body type, results can show by the month, but again, if you were almost there then you'd see it faster. A guy like me will wait forever before seeing the results I want.

Calisthetics is where its at if you're doing this at home. You can do chair dips for your tri's, push ups for your chest, etc.

You can modify your pushups by putting on a bookbag to add weight...works good.

There's a lot involved, but if you eat right, and alternate your workout daily, then you'll be good to go. You can do your abs more than 3 times a week. Unlike the rest of the muscles in your body, your abs are constantly being used. They can take what you throw at it. I'm def. not saying an everyday ab workout, but if you wanna bump it up, go ahead.