Become known for what actually happens after you say you will handle it.

Everyone says they will handle it. The reputation forms in the gap between saying and what actually occurs, and people track that gap closely even when they never mention it. Being known for the second half rather than the first is worth more than any amount of confidence.

Count how many things you have said you would handle this month and how many are done. If the numbers differ much, take on fewer and finish them.