Thien's tire got slashed by a piece of glass on our post-work ride today. This gave me a chance to spy his $20 patch kit, which is one of the easiest to use that I've seen. I thought I'd share.
Step 1: Prepare the patch kit by folding it twice over
Step 2: Locate the gash in the tire
Step 3: Insert patch kit between tube and tire
I plan on undercutting him by offering a $1 kit -- $2 for double strength.
You can learn plenty more expert tips like this by participating in the RoadbikeReview.com Peninsula group rides.