Please watch at least two of the welding videos below. The first two are best but all of them are helpful. They explain safety and technique far better than we can at the shop.
Basic MIG Welding
This basic MIG welding class is very good.
Advanced MIG Welding
Make sure to check out his tip at minute 15!
Welding – Tips for Beginners, Types of Welds and Troubleshooting
These are excellent tips for beginners.
Flux Cored Wire VS. Solid Wire (MIG)
Flux Core