Your integrity is everything. It precedes you and follows you. So make sure you follow your words with actions. If you promise to do something, make sure you give yourself enough time to deliver and deliver on time. Then follow-up and do it. Be accountable. If the request is not something you feel you can deliver, either say no or negotiate to a point until you feel you can deliver. There is an art to ‘under promising and over delivering’. The key is it is OK to pad the schedule to make sure you have time to complete the request while balancing your other work. People probably won’t remember if you negotiate the delivery to a later date when you are agreeing on the timeframe, but they will remember if you miss a deadline. So say what you will do and then do what you say.