Along with a welder, get some training at a local vo-tech. The instructors typically come from industry with years of field experience, and are able to impart their knowledge and experience via hands-on instruction. Procedural knowledge is absolutely necessary, but no amount of reading will beat making arcs and sparks. Another advantage of getting into a vo-tech is that the welding shops typically also have huge shears, press brakes, and a variety of materials. When you only need a 2" length of 1/2x6 to make a bracket, this comes in very handy.

I had taken training in SMAW (shielded metal arc - aka stick welding), GMAW (gas metal arc - aka MIG), and GTAW (gas tungsten - aka TIG), and thought I was good until I worked at a fabrication shop. My welds were both mediocre and slow compared to others, but after three months welding six hours per day, I am no longer an amateur. The job folded after nine months, but welding at that level is like riding a bicyle.

I have a 15 year old 130 amp L-Tec (Linde) 110/220v GTAW. I've made qualified one-pass welds in 5/16" carbon plate with .035 solid wire with this unit and the correct procedure. If I need anything larger, I take the project back to school (where I'm still friends with the instructor) and have access to 440v industrial welders in many flavors.