Hiya Erin, glad you stopped by. I was going to post this response to your questions in the comments section, but it got really big, and besides, it all bears repeating because (hoists self up onto soapbox) everyone should be growing at least some of their own food, and now more than ever.
You'll be happy to know there's so much more to container gardening than tomatoes. A great book I recommend is called "Movable Harvests" by Crandall and Crandall. It talks about soil mixes in detail, very important in container gardening. Another book is "The Bountiful Container" by McGee and Stuckey. That book has a big following, but personally I find it too cutesy, with far too many pages dedicated to edible flowers. Also, I prefer photographs to line illustrations- the former has photos, the latter does not.
Ok, some advice!
My number one piece of advice- If you're new to container gardening, start small the first year. If you try to grow too much you'll be completely overwhelmed and probably never want to do it again. There's a lot to learn, and you learn it plant by plant.
My number 2- Grow what you like to cook and eat, plain and simple.
Number 3- Think vertically. Any vining plant (squash, peas, pole beans, small melons) can be tied and trained upwards with poles, trellises and twine. If given a choice, grow vining varieties over bush varieties. They are usually far more productive.
Number 4- Get potting mix, not potting soil. There are important differences between them, number one being that roots need a lot of oxygen and potting mix allows for much better aeration. Potting soil will compact quickly and stunt your plants. Don't be attracted to the giant bags of topsoil for vegetables, they are mixed for in-ground gardens. Container gardening is a horse of a different color.
Hope that helps. If you have any specific questions, just ask.