Last year we had to get rid of a few of our garden beds to make room for a greenhouse. That means after the beds were built we then added lots of compost to get the soil ready in those new beds. We also rotate our beds every year to prevent pest and to keep diseases down. Some plants like very rich soil and others do not.
We have 12 garden beds.... In the spring when we built our new beds we added the soil that we got from the beds and we then added at least 2 inches of compost to those beds. At the end of the season we add compost to all our beds to let the soil get rained on and snowed on until spring. The older beds have had this done many seasons so the soil is so rich...and some plants like rich soil (heavy feeders) and others like leaner soil not as fertile (light feeders).
Heavy feeders like (rich soil) : beans, swiss chard, broccoli, cauliflower, kale , celery, corn, asparagus, cucumbers, melons, pumpkins, artichoke, lettuce, eggplant, peppers, and tomatoes.
Light Feeder like (leaner soil) : beets, radishes, turnips, carrots, parsley, sweet potatoes, potatoes.
You can improve your soil by adding heavy feeder's like spinach in the spring you then can plant beans right in their place in the summer. The soil will become richer because you had the spinach there in the spring..like wise if you have a light feeder such as peas in the spring replace them with another light feeder such as carrots in the summer.
Now...the next year you should rotate those beds... you should plant your spinach in the pea bed and so on... This is how I rotate my beds I never plant the same plants in the same beds each year and that includes plant families such as broccoli and cabbage they are in the same plant family...this means they get the same pests and diseases.
If you get nervous and can't decide what to plant and when...I suggest you plant beans. I believe beans plants are the best thing for any type of soil....it adds nitrogen to the soil and this will help any plant you plant afterward.
A few suggestions:
The first year I plant tomatoes and the next year green beans
The first year I plant parsley and the next year carrots
The first year sunflowers and the next year green beans
The first year green beans the next year sweet potatoes
I hope this helps you understand crop rotation...I would love to hear how you rotate your garden beds.