I think something to watch out for when practicing execution for moves is, to first of course..
1) practice slow....for instance, umvc3/mvc3/ssf4ae/ ryu's hadoken is
+ [punch]
Even if you do it slow and a fireball doesn't come out, you still got the motion out. Here is the HARD part.
When the input is ON in practice. you should see a consistent
+[punch] back to back.
I say this because you WILL often do (ssf4ae input style)
[Punch]
[punch]
vs the correct way
in both inputs a fire ball will still come out. But execution for strict timing games like KoF will help you improve your combos and help with super/ultra/neoMAX/etc etc.
2) They say to be good with your motions practice doing a move/combo/set-up about 10 times no mistakes.
If you mess up once, don't cheat yourself, start over from 1.
PRO's of course practice these moves over a 100 times no mistakes. This is what truely separates "men from the boys"
This should eliminate mashing. Reason you mash of course is mashing out "hope" lol
just know your inputs. practice your timing and moves. and of course get alot of play time in so you don't scrub out a mashed out super/ultra