You'd be surprised what you can grow successfully in pots.
First off, concentrate on things you really like, that are easily grown in pots with some minor care and attention: You could choose from, say... tomatoes, potatoes, herbs of various types, lettuce, french beans, small carrots and baby beetroot. Tomatoes need the most care out of these, but none should be difficult. Make sure that when you choose varieties you look for those which are compact rather than large and spreading - it makes things easier when you're starting out.
In terms of fruit, strawberries are a doddle. Buy them as small plants - seed is much trickier.
Once you have done a few "easy" ones, branch out a bit to other things you like. With a bigger container, you could have a courgette plant, for example. Calabrese (green broccoli) can work well and a really sunny spot would be a great home for peppers and chillis.
I have tried just about everything in containers and the only things I would suggest you avoid until you have some ground space include:
standard sweetcorn (it can be grown in containers, but you need a few plants which makes it more difficult).
purple sprouting broccoli - very big plants
brussel sprouts - big plants
perennial crops such as asparagus or artichokes.
Of course, a lot depends on the size of your containers - you can grow trees in pots if they are big enough!
Once you get going I think you'll be pleasantly surprised with what you can achieve in a small space. It's a really good time to be planning things, so start making a list and get some seed.