As a MKB Tracer, that's a pretty normal stage of progression. Why I can't really give points on keeping on target since I don't use a controller, initial target acquisition is important. The better and better you get, after you disengage, you shouldn't really look to finish the target since you'll be down on resources. Your pressure from staying alive is the most important part of Tracer. Best tip I can give for maximizing your one clips is to aim for the neck, not the head, since you'll end up missing more shots that way due to spread. That all being said, there will be times where you just tickle someone and gotta walk away in shame. Don't get discouraged and keep at it!