"Fall is for planting", and the best garden preparation known is to provide a deep, enriched root run for newly transplanted plants to get a good start.
1. Rake off duff
Typically there is a layer of dried grass, leaves and sticks that is best raked off and composted
2. Take soil samples and do a soil test
Samples are small amounts of soil taken from several locations throughout the bed, then mixed together and tested for pH and nutrient levels. Try a kit or send to the cooperative extension service.
3. Dig out dead plants, old roots, weeds, rocks, sticks and so forth. Cobalt blue bottles, maybe. Old or dead shrubs, roots, rocks, weeds and so forth are best removed from the planting bed
4. Turn soil over leaving big chunks
Your garden spade should break through compacted soil and turn big clods
5. Top dress with compost, Nature’s Helper, Mushroom Compost, Mr. Natural, finely ground pine bark, or dampened peat moss, plus gypsum or pulverized, dolomitic lime according if your soil test feedback calls for it
You can’t go wrong with adding organic matter: clay soils are lightened while sandy soils hold more water and loams are enriched. Add 2 or 3 inches on top of the cleaned bed. Other possibilities include blood meal, cottonseed meal, triple superphosphate, symbiotic mychorriza, well-rotted manure, well-rotted woodchips and so forth
6. Fork organic material and amendments into soil
My spading fork prevents me from lifting soil that is too heavy
7. Water in
If you have a few hours, water in the amendments and let everything settle
8. Rake smooth
A steel rake lends a calming influence on a prepared bed. The soil should now look just like a chocolate cake. Resist rolling in it.
9. Set out plants, then plant into prepared bed
Spread out roots of container-grown plants and plant level with the top of the soil or slightly higher
10. Mulch with organic mulch
I use pine straw or ground pine bark, but pecan hulls, salt hay, compost or whatever common mulching materials are available will help protect the bed and insulate the root systems. Water thoroughly once planted.
Photo 2 shows a bed prepared between a house, a Nandina and a border of Liriope.and spread with Nature's Helper.