This is where carefully removing the tube, marking it, and submerging it if necessary (rarely is) to find the hole is helpful.

If you are pinch flatting you need more air or are installing the tubes wrong-- twisting or pinching them. Pinch flats look like a snakebite most of the time but can be more of a tear.

If you are puncturing in recurring spots, that spot of the wheel or tire has something sharp.

If it is multiple puncture locations I would start with Mr Tuffy and see if that helps.