Only promise what you can deliver!
Delivering on your promises is doing what you said you would do, when you said you would do it.
If you always do exactly what you say you will do you will build a very strong relationship with your colleagues, managers and customers. If you can deliver more than that, then better still!
Under promise and over deliver whenever possible!
Many companies use this principle to build trust and strong relationships between all levels of the organization and its customer and shareholder base. A classic business example is Apple’s constantly low guidance for revenue and profit and over delivery every single quarter.
Be always true to your word – if you promise something, deliver it. Don’t question your own promise after you have made it – you are obligated to fulfill it.
If you promised to deliver a sales presentation, make sure you are there on time and well prepared. If you promised to organize a meeting make sure you thought of everything needed. If you promised to sit in for your manager, make sure you are there and very well prepared.
Remember that a promise should be voluntarily – this is the second part of you promising something – only promise what you can deliver.
Do not let anyone pressure you into promising something you already know you will not be able to deliver. If you are sure you cannot do it – do not promise it. Say no (read also: “Never say No!”), make clear it is unreasonable and explain why – this is very important: You have to make sure that it is understood why you will not promise something, if you don’t explain people might think you implicitly promised something that you didn’t.
Unfortunately it is part of today’s business world that people will try to force you into decisions and promises - be aware of that and don't accept it.