When you say no, stick to it. It's the only way to get control of your day. Pick your battles, say it politely, provide alternative suggestions and don't back down.
Maintain focus in meetings. If a meeting seems to be wandering, bring it back on track. Ask others what they want to achieve, then decide together the most time-efficient way of getting there.
Make the most of dead time. Always have a list of ongoing projects noted somewhere (at the back of your diary, say, or on your BlackBerry) and carry it with you wherever you go. You can work on these items while you are waiting for meetings or stuck on a train.
Match task to mood. Decide what times of the day (or week) you have your highest and lowest levels of concentration and organise your activities accordingly.
Spend time with the people who are difficult to get hold of. There are lots of people who want to spend time with you, such as salespeople from potential suppliers, and they can be the worst time-parasites. Your time is better spent with people whose diaries you have to fight to get into.
Imagine your diary is clear. What things would you focus on at work if you had all the time in the world? Now get on and do them. Others in your team will pick up the critical pieces and no-one will notice the rest.
Groom people. When you hand over projects, give enough guidance so that the person builds their skills, rather than just obeys orders. This will make them keener to take on more from you next time.
The Mind Gym: Wake Your Mind Up is published by Time Warner (£12.99), www.themindgym.com.