Don't bother trying to fix a hole in the tire unless the cord(s) are broken- no need to fix otherwise.
If the cords are broken you'll have use a material that is as strong as the casing of your tire. I've always used "dead" silk sew-up (tubular tire) casings to make tire patches. You might try the sidewall/casing of a good quality clincher or a very strong fabric. When you make your patch be sure it covers a wide area around the hole so it will give adequate support and not "flex" loose, for lack of a better description. Try to get your mating surfaces as clean as possible and "roughen" them a bit to improve adherance with your adhesive/glue. Don't forget to dust the area with talc (baby powder) so your tube won't stick to the tire, possibly causing another flat, also suggested when patching your tube .
If you need a quick fix on a ride to keep the tube from being exposed- stick a mylar (Power Bar) wrapper or a piece of dollar bill beween the tube and tire.
I always carry an old foldable tire with me in case of a slice, tear or blowout. I've very rarely needed to use it but when I did I was VERY happy I'd carried it along and REALLY needed it in the middle of NOWHERE.
Tufo (sew-up makers) Market some liquid latex type stuff that works really well and uses less "liquid" to do the job, hence it's lighter and you can get it into Presta valves by taking out the inner valve assembly. I made a "straw" out of a brake housing by cutting a bit of the plastic from each end to fit into the tube of latex and the valve hole to make it easier to get the junk into my tires. Damn, it's nice not to throw away or fix sew-ups anymore

[Edited by pat5319 on 12-12-2000 at 03:37 AM]