If you are ready to make a salad, salsa or sauce within a day or two, the most important thing is to pick a ripe tomato. Look for a vibrant color, as well as one that is plump and firm. The tomato should be free of wrinkles.
For your tomatoes to last, do not refrigerate them. Keep them at room temperature. If you bought tomatoes that were not ripe and want to speed the process up, you can place the tomato in a paper bag with an apple. The apple emits ethylene gas which helps the tomato ripen faster.