Tire changing, fixing a flat, the bane of the cyclist. I came across this video today, which is in my view a good illustration of the process. Great to watch if you are new to roadside repairs. Just make sure you carry a spare tube for your bike (I carry two) plus spare patches. I personally like the Park Tool Super Patch Kit which works without glue. They seem to hold okay with my high pressure tubes (pumped up to 120 psi). You can find the video here.