Make sure you know if your tomato is determinate or indeterminate . Some tomatoes are meant to be pruned and stems can be snapped off, others will be hurt by this. This information will be found on the seed packet, or seedling label, and can be found online/in books.
If you want a short, bushy tomato plant, choose a variety that is meant to be short and bushy. There are 100s of types of tomato plants available.
