Taking a series of classes is the way to go... I have some experience with stick welding, tig welding and mig welding but I wouldn't feel comfortable building anything without putting in at least twenty or more hours of practice on any of the above. Then there are considerations of tube thickness, materials, etc. that would change your settings so it's difficult to just "cookbook" it without having a solid background. For me, at least, I know that TIG is my preferred technique so if I wanted to get better, I'd probably find someone willing to give maybe ten hours of one-on-one lessons over a month and then I'd practice a ton.

MIG vs TIG... I just prefer to hold the wire in my hand rather than having it fed from a machine.