Don't forget to add the date onto your seed packets when you're storing them. In some cases they will last more than a year and you might need to stagger planting and harvest, so it's better to know exactly when and where each crop came from.
You might also want to think about genetics a little bit when you're selecting your seeds. If one plant did exceptionally well, that's the one you should be collecting from. Maybe not exclusively, though, as it's never a good idea to keep all of your eggs in one basket.