For me, my break completely changed in efficacy via one change in follow thru.... and most importantly, time away from the game (YEARS in fact) is not nearly as impacted by loss of muscle memory.
I think a lot of folks just try to smack the CB at or near mid, mid-top. I used to as well.
Then I got a 20 oz 'breaking stick' from a pro who won it as a door prize, and had a friend put on a phenolic.
I place the CB as near and straight on the spot as possible, sometimes measuring the absolute limit of closeness by placing said breaking stick across the 2nd foot spot diamonds.
When attempting the break, I pick out a spot on the table about 1 ball length to 3 inches BEYOND the top of the CB, using the height of my eyes thru the CB into the table as my reference point.
I then strike the CB trying to skewer that spot thru the CB, as if it were invisible, as if I'm actually hitting 'thru' it, to that spot.
I just potted my first 8 ball on the break in many years, ironically NOT in the side, but the right corner.
Talent disclosure: I have a ceiling at B-, but due to technique, I can always come back as Straight C after Years away.