Step 1 - remove ring screws.
Step 2 - remove scope and rings.
Step 3 - Remove bases - visually inspect threads in receiver area - if not stripped, degrease.
Step 4 - Install bases properly, with a lok-tite or similar compound made for this (the kind that allows for removal later).
Step 5 - Re-mount scope to fit you with ring screws (degreased) just tight enough to hold the scope, but loose enough for it to slide. This means with eyes closed you establish proper shooting form with a good cheek-weld to the stock, then open your eyes. Start with the scope forward as far as it will go and move the scope backward until you have a full sight picture when you open your eyes.
Step 6 - tighten rings screws. You may also use lok-tite on the ring screws.

Be sure your crosshairs are vertical/horizontal before tightening.