One thing I have learned over the years is that soil testing can be your friend. I have built several new garden spots over the years. Usually in clay and slate rock conditions. A soil test will tell you what your soil needs to be prodcuctive. Simply adding manures and compost willy nilly is just guessing at best and you can just as easily overdo the compost and manures as you can the chemical fertilizers. Different manures will have different nutrient levels. Pastured cattle manures will generally be higher in Potassium (K) and nitrogen (N) than it will be in Phosphorous (P). If the cow manure comes from a feed lot where the cattle are fatten on grain, dont be surprised if the P levels are higher than the K. The manure will be the result of what goes in and grains contain more P than K and grass contains more K than P. Horse manure is considered a balance manure with almost equal parts P&K. Chicken manures are high in N, but almost balanced in P and K. Sheep manures are similar to chicken but can contain higher N levels. Alpaca manures are very high in N, more so than either chicken or sheep.
All manures should be composted prior to using. This reduces chances of a nitrogen growth spurts and also helps reduce the chance of salmonia and eboili bacteria contamination. The compost doesnt neccesary need to be incorporated into the soil and actuall using the compost as a mulch will produce better results and help control weeds. It can be incorporated at the end of growing season when you are getting your garden ready for next year. I heavily mulch between my rows each year. it conserves moisture and provides a ready food source for the microbes. By the end of the growing season, it pretty much dirt and I just till it into the soil and plant a cover crop.
While tilling the soil helps to break it up, making everything easier to work in, excessive tilling destroys the soil structure and will create a stratisfied layer of loose soil and compacted soil. The surface just under the tilled surface will look just like the top surface, slick and smooth. If you are going to till every year, consider adding a subsoiler to your implement list to breakup the subsurface of the soil for better water penetration.
In my experience a no till garden where the seeds are just drilled in and the sod left in place between rows, will usually hold more moisture and produce more crops than a tilled and plowed garden. Especially if the rows are left wide enough to run a mower between rows. Like most folks, I dont use that method, preferring to plow and till instead. Never have figured out why I want to work harder than necessary just to grow a garden, I guess its because thats the way I was taught growing up.
