Pattern Drafting Tools and their functions :: By: Isn't that Sew Read this has some good tips. If your starting out just buy the essentials. Tip: Measuring Tapes check against metal rulers every so often they will stretch after frequent use.
I have this incredible skill that has saved my family hundreds of dollars(quite honestly, it's probably more like thousands). I'm self taught (mostly) and other then a below average semester of Home Ec back in grade, I've never taken a formal class.