Personal experience on raised beds. They dry out way too easily and require a lot more watering. Having a dense soil may be an issue but ours is considered second best in the world.

Seed saving is key

Tomatoes: use heirloom or you’ll get a different variety. Remove seeds and liquid. Let ferment in a covered cup for two weeks. Rinse and dry on wax paper.

Peppers. Use fully ripe fruit. Remove seeds

Lettuce and other greens. Let bolt. Also some herbs as well.

Carrots are biennial so let a couple stay in the garden and next yr you will get A fluffy ball of seeds.

Beans and peas. Let dry on the plant and remove the seeds from the pods

Onions. Plant a variety like walking or egyptian onions you’ll get green onions and smaller bulbs. Chives too are good as they return every yr

Squashes are the whores of the garden and cross pollinate so if you save seeds only plant one variety and away from neighbors. But squash seeds are good parasite cleanses and very nutritious. Save and eat

Garlic. Plant fall before

Potatoes save for next yr planting

Melons. Save the seeds

Flowers too. Always nice to have some beauty.

And so on. Your own seeds will germinate more quickly than any purchased.