I've found that in order to be good at giving head you have to believe that you are good at giving head. Attitude is more important than specific technique. Also, the "pause" is more critical than the "play". If you just pretend like you are a high-class hooker who is an expert at giving head, you'll probably be quite successful. However, I wouldn't recommend making this suggestion to your wife. LOL
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver