If I am in the shop, I use a slack belt grinder - not recommended for the beginner. I like an appleseed edge on field knives. The edge lasts much longer. Typically, I do 22o grit followed with green chrome rouge on the buffer. This give a good general purpose edge with good cutting. Too fine an edge and you will have an edge that is good for shaving, but not particularly useful for slicing or cutting. You ideally want those micro-serration, but no wire edge.
If I have to hand sharpen, there is no substitute for traditional wa****a stones. If you need more, a good surgical black does the trick. For my stright razors, I use synthetic waterstones from Norton. 8 inch stones can be had in grits up to 8000, at a lot less money than natural stones. They also tend to be more uniform. Finish is with a horsehide strop.
For really tough steels like D2 or S30V, stones are next to useless. You pretty much have to use diamond or ceramic, or a belt grinder. Again, the edge is finished with a buffer and green chrome rouge.