A lot depends on where you ride and what is causing flats. I use kevlar-belted tires on all bikes, stay out of the gutter and watch where I'm going. This helps keep flats to a minimum. Fortunately, I don't have to deal with things like goat heads around here. If I did to any extent, I might be looking at tire liners and/or self sealing tubes.

Also, make sure you are getting whatever caused the flat out of your tire when you make the repair. That, and running tires that are worn thin, can lead to recurring flats.