make sure your basic skills are good before beginning to shoot in competition
Make sure that your basic safety & marksmanship & gun handling skills are reasonably well developed before you attempt to shoot IPSC/USPSA or IDPA type matches.
Safety is a major concern. Some people get way too nervous at their first few matches and forget about keeping their finger off the trigger unless on target and ready to fire, and keeping the muzzle pointed in a safe direction at all times. Another issue is courses that involve movement, or opening doors or windows. Be careful not to sweep yourself with the muzzle when opening doors.
Make sure your basic skills are strong before you try to shoot in a match OR forget about trying to be fast, and just focus on being safe, accurate and smooth.
One of the shooters in my pistol club is a young guy (just turned 21) who is athletic and coordinated and naturally "fast" HOWEVER he hasn't been shooting very long, and doesn't practice basics enough. When he come to a match, he's faster than h*** but he can't hit anything. For certain he jerks and bashes on the trigger, and I suspect that he sometimes forgets to look at the front sight. After watching him shoot the last match, I noticed that he also squeezes his whole hand while firing ("milking") rather that moving the trigger finger independently as a unit. I don't think he does that all the time, but only when he's trying to go really fast.
What he needs to do is a basic shooting course like MAG 20 (what used to be called "stressfire") or Gunsite 150. But he doesn't see it that way, and would instead rather try to find a competition oriented class to go to . . . which I think may not correct his problems.
You can only learn from experience if you pay attention!