Every time you keep your word on something small, you make your big promises believable.

Reliability is built out of items too small to remember. Turning up when you said, bringing the thing you promised, replying when you promised: none of it is impressive alone, and together it is the whole basis on which anyone decides to believe you later. Nobody can verify a big promise in advance. They can only look at the small ones.

For the next week, say yes to less and then do all of it. If you cannot manage something, say so before the deadline rather than after. That one habit will separate you from most people.