When you do have to decline something, here's a technique that may help: acknowledge the request, but clearly explain your reasons for saying no. Then suggest an alternative solution. To illustrate this approach, here is an example of a response you could use:
'I can see how important this work is, but I can't take it on as I am already overstretched. My suggestion would be to postpone the start of the project. If you could wait for a week, I could take it on with pleasure. Or we could ask Millie to step in. How does that seem?'
The answers to the questions below are not easy to gather, but they are very useful.
Define your business priorities and goals.
Revisit them on a weekly basis and share progress with the team.
The next step is to put these ideas into action. Finish by recording your learning outcomes.