I use:
- Flat resistant tires (like other posters)
- A spare tube (leaks around the stem can't be patched)
- Postage stamp sized self-adhesive patches in case I get more than 1 flat on a ride

Like other posters I don't get many flats since flat resistant tires have become available.

Before flat resistant tires, found I didn't like glue patch kits from experience. You use them once, then usually the glue tube glues itself shut and can't be used again. If you forgot to replace it you have no usable patch kit when you needed one, and it was easy to forget to replace at the end of the ride.

In contrast, you can carry 5 or 6 self-adhesive patches in one tiny container giving you 5 or 6 times to remember to restock them on the bike. So I prefer self-adhesive patch kits over the glue kind - though like I said I'd start with flat resistant tires to avoid needing to use them to begin with.