Choose seeds for a plant that you or family likes to eat.
Choose a non-hybrid, open pollinated heirloom variety.
Understand how each seed is pollinated. Choose a seed that is self-pollinating like tomato, beans, lettuce, or peas. These plants are pollinated before the blossom opens so you do not need to hand pollinate.
Enjoy harvesting produce but keep some seed to mature on the plant. (Leave some bean and pea pods to dry and mature on the plant, harvest tomato seed from a few of the best fruit.)
Saving seed is not difficult; our ancestors did without fancy equipment or degrees in gardening! Check online for best seed saving practices for each variety from planting to seed harvesting. Harvest the seed, air dry it, put it in envelopes and store in cool dry place till next spring! You are now a seed saver!