Every excuse has a fear hiding behind it. Name the fear and the excuse loses its job.

Excuses are rarely lies. They are usually true facts promoted to reasons because the real reason is harder to say out loud. You are busy, that part is genuine, and it is also covering the part where you are afraid of being bad at it in front of people. Once the fear has a name, the true fact goes back to being only a fact.

Take something you have been putting off and finish the sentence honestly: you have not done it because you are afraid of what. Say the answer out loud once. Then decide about the thing itself, with the excuse out of the way.