It doesn’t matter how good your movement, aim or positioning as Tracer is. If your pulse bombs don’t land you won’t be able to reach anywhere near Tracer’s full potential, as it is the most important and strongest part of her kit. Landing a good pulse bomb, however, can be hard, as it is a projectile that flies in an arc at a relatively slow speed, and especially in a relatively fast paced game like Overwatch where most characters are rather slim, it is not always easy to land the stick, even for professional players.
There are however some ways you can make your pulse bombs more consistent. For example, you can try to stick enemies that are larger. Most tanks like Reinhardt, Roadhog or D.va are incredibly easy to stick because of their size, and as the tanks they usually position themselves very close to their team, allowing you to get at least 1 kill with it almost 100% of the time, as longs as you follow up with a clip.
Against a Reinhardt, you can also come from behind and throw your Pulse bomb. Even if it misses Reinhardt himself, it will most likely attach to his barrier. While good Reinhardt players can play around that, most won’t be able to react quickly enough and take the full force of the explosion, and some Reinhardt players even turn around out of panic, rotating their shield and thus your Pulse bomb right into their team!
D.va is also a character that is really important to take out early. One way you can guarantee value out of your pulse bomb is by waiting for her to reenter her mech. When a D.va uses her Self Destruct, she will be able to reenter her mech immediately after her ult explodes. You can blink towards her as she reenters it, stick her and shoot a clip as a follow-up. She will lose her mech immediately, being essentially useless for the rest of the fight!
Zarya is another character that can give you super easy Pulse bombs! Simply wait for her to use her barriers on either herself or a teammate. Wait until the barrier is about to run out and throw your pulse bomb towards the barrier. The barrier is huge, and thus hard to miss, and if you time it correctly your bomb will detonate after the barrier fades, allowing you to take even very hard to stick characters like Mercy or Lucio out of the fight!
Sometimes, however, you have to land a stick on a key target that isn’t Zarya bubbled or a tank. In those situations make sure to always aim for the legs! This way, you can make sure that the pulse bomb reaches its target as quickly as possible (Remember that it flies in an arc!).
Not only that, this way it will hit the ground below your target in case it won’t stick, instead of flying 2 meters behind him, which can still net you a kill and minimzes the impact a missed bomb may have!