I learned to weld using three simple moves: First, I went to a welding supply shop and asked the guy there to explain it to me. In 15 minutes he told me everything I needed to know to get started: With a mig welder, adjust the amperage (heat) depending on what you are welding- thicker=higher, adjust the wirespeed the same way-thicker slower, thinner-faster. Pull some wire out of the tip of the welder, cut it off so you've got about 1/2 to 3/8" of an inch, put the end of the wire where you want to weld, pull the trigger and start moving the tip along the weld- If it sounds like frying eggs or water sizzling in hot iron pan, you're doin' good!
After hearing that I got a book on welding, flipped through it a few times and picked up some scrap metal pieces and burned through a spool of wire practicing.
I have no doubt that I need to learn lots more about it and one day I will take some classes. Meanwhile, I feel comfortable doing the small welding jobs I need to do, including patch panels. A trailer hitch I might cut, spot weld and then take somewhere to be finished.