Divide and allocate your time. The people you want to spend time with (eg, clients) won't often be those who want to spend time with you (eg, potential suppliers). Decide what proportion of your time you will spend with each audience and stick to it.
Work with your natural body clock. Decide what times of the day (or week) you have your highest and lowest levels of concentration. Then either match tasks to your mood or deliberately mis-match them (eg, plan meetings when you have to perform to override your low concentration times).
You will never get everything done. Focus on the things that will do most to help you achieve your goals, or that you can complete quickly, and don't worry about the rest.
Practice good timekeeping. Start your day promptly and make being on time for each appointment important. Lost minutes here and there soon add up to lost hours.
Always have a list of ongoing projects. Keep it with you and work on it while you are waiting for meetings to start, sitting on a train/plane or at any moment that would otherwise be dead time.
Finish tasks as you go. One of the most common time parasites is not completing something, so that you have to start from the beginning each time you return to it. Once you've started, don't stop until you reach a point that it will be easy to pick up from.
Take a stand. Much of our time is spent reacting to other people's requests. Next time someone asks you to do something significant, stop and think about whether it is the right thing for you to do. If it is, think about how you can go about it time-efficiently. If it isn't, say no. 'No' is the most useful word in time management. Say it politely, clearly and as often as required.