I use 85/15 ground beef. This is primarily what I always use. It gives just enough meat and just enough fat to flavor it. Too lean and it won't taste the same. Its all up to the individual tho. Now for every pound of ground beef you will need the following. In this case we are only making 1 pound. There is no particular order for any of this.
1/2 chopped onion
approximately 2 heaping teaspoons of jarred granulated garlic)
approximately a couple tablespoons of Romano cheese
approximately a tablespoon of salt
approximately a teaspoon of ground pepper
approximately 2 tablespoons of dried parsley
approximately 1 cup breadcrumbs (Italian or plain)
Put in the bowl and hand mix until well blended. Ball your meatballs. Now you just need to cook them. I usually fry them until the outside is brown and it seals them. Then stick into Sunday Gravy (spaghetti sauce) to cook the rest of the way. You can also bake them.