What makes glasses more comfortable to wear?

Made correctly: Glasses need to sit comfortably, have the right correction for the glasses and need to be adjusted so they sit in the correct position on the face. Proper alignment will help a lot.

Specs comfort: The right prescription and the right fit. If you feel strain, you may need your eyes dilated and then the rx checked that way, or a red/green test. Otherwise ods sometimes over-minus you, give you too high a rx, which causes eye strain. A good optician to fit your glasses onto your head helps. That said, the best optometrists usually give better rxs than an average ophthalmologist (eye surgeon).