To do it by hand:
Mount the wheel. Spin the wheel slowly while tightening the nut too much, you will feel the drag go up quite a bit when they are too tight. Back off the nut and then retighten it until you feel it "firm up" in the wrench or channel locks (what I use). stop the wheel from turning and grab it top and bottom. see if you can feel any rocking or slack in the bearing. If it feels tight, then you are in the right range.
Tapered bearings need just a little bit of pre-load in them to work right. It's definately a feel thing. If your unsure, get a wrench. But if you do it this way 3-4 times, you will begin to get a feel for it and you will know when the slack is gone and the preload is in.
Befrore becoming a master mechanic back in the 70's and 80's I learned from a master and spent a WEEK making these adjustments on a junker outside the shop. Every day, I had to repack, mount and adjust them until he was happy. Frigging task master was old Morty.