I encourage people to work with Action Lists rather the never ending To-Do List. Each morning create an Action List of the things you need to get done that day. These should relate to your overall goals. Do the important things before they become urgent, don't waste your time on unimportant things that really won't make a difference to your business or your personal life.
Plan the time into your day when you're going to do these actions. Make sure you prioritise them and do the No.1/High priority tasks first before anything else. Once you've done all the important things you can then work your way onto the next set of important actions. You'll find that things that you have as low priority, trivial tasks tend to disappear off the list. Easy or low priority tasks can also be scheduled into the day as a break between harder, high priority tasks. Group similar tasks together - like making phone calls or writing emails. It increases your productivity.
Don't over stretch yourself. If you only have time for three things, don't create a list with 20 things on it. Keep your action list short, realistic and focused. If you get them all done, take the next thing and do that. Achieving everything on your list in one day can give you a great sense of achievement
Keep a master list so that you don't forget things but prune and prioritise this regularly. Write a list each month of what you want to do and refer to this when you're planning your weekly and daily actions.