How to:
Wipe tire down and inflate. Many times you will be able to see or hear the leak. A little soapy water helps.
Mark leak and pull out the offending debris.
Deflate tire and pry off one side. Remove tube. If you didn't find the cause of the leak remove the tire and examine the inside.
If you didn't find the leak inflate the tube again and use the soapy water to find it.
Dry tire and lightly sand the area.
Apply glue and let dry for 2-5min then apply the patch.
Let dry overnight. But I have used patched tires within 20 minutes with no problems.

I wipe my tires after every ride and look for those nasty little wires from ruined car and truck tires. Better to remove debris before you get the flat. I think I have cut my flats in half by doing this post ride ritual.