If you have the room, consider a compost pile. When we bought our property 6 years ago, I took an area and started with leaves, fruits and veggies scraps, egg shells, old potting soil. I would turn it over often and leave a ridge down the center for rain. Last year a friend up the road had a huge pile of horse manure that was thoroughly aged (like 5 years!) that she needed to get rid of. Many trips with my trusty Kubota and I had a lot of manure to add to my "pile" . In the fall, I added some more leaves and continued turning it over several times a month.
The result has been a rich soil with a lot of worms that I have used to top dress all the plants on the property and used to pot up annuals; in addition to potting soil. My soil is very sandy.
My pile is about 8' long and 5' wide. If you have the room (and access to manure), this is the way to go! Beware of fresh manure, though. It is hot and can burn up plants.