When patching an innertube be sure you hit the area around the hole with the sandpaper that's usually provided in patch kits. This abrad3s the surface of the inner tube so there's tooth to the surface that the glue and patch can adhere to. Make sure the a raded are is slightly bigger than the patch so the edges of the patch can adhere to the innertube.
Before applying the patch glue on the inner tube, make sure you clean the innertube's surfacce very well so there's no dust, moisture or sand on it.
This is the step that most people fail to do, which results to the patch not totally adhering to the innertube.
I never had a patch fail on me all the years I've been cying, using the procedure above.