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.