The Park glueless patches work really well for me. I think the secret is to make sure they are firmly stuck on before putting the tube back in. I use a rounded edge of a tool (multi-tool or tire iron) to squeege from the center out. Make sure that there's no air bubbles between the patch and tube. You can tell by the color- the patch goes from opaque to clear where its firmly stuck on the tube. You have to pay extra attention to where the patch goes over seams on the tube.

Glueless patches also work as tire boots, if you haven't packed a section of Tyvek race number or cut the beads off a chunk of old tire and put that in your pack.