Getting To Zero
The key with clearing things completely is to get to zero, in terms of how much the specific issue bothers you.
Firstly, once you get to a 1 or 2 (on a scale of 0-10), it can feel hard to make progress. So, if you imagine diving right into the problem, make it as big, real, and colourful as you can, you may be able to get it up to a 6 or 7 in your mind. Then tap again. That will help clear out those last little dregs.
Secondly, it's important to work on every single emotion that comes out of a specific traumatic experience.
Particularly with very traumatic situations, we can have many strong emotions come out of the same event: Anger, pain, distrustfulness, disappointment, lacking safety, feeling betrayed etc.
This is kind of the opposite of having many situations contributing to the same upsetting emotion.
Sometimes you'll feel energy welling up in you, but only when you tap on one specific point. It can be helpful to keep tapping on that point until the energy goes away (often signalled by a yawn, burp, tears etc).