What I've found effective:
1. Waking up at the same time every day (preferably early) - There's something about waking up early at the same time everyday that stimulates me. Like Steve,
2. Making a list of what needs to be accomplished (and do it) - This is a very basic way to stay organized, but it is highly effective.
3. Physical exercise - It helps keep your energy levels up and will thus give you more motivation. When going without exercise, many people feel lethargic.
4. Do it all at once - If you are going to eliminate clutter from your room for example, I have found it helpful to do it all at one time. E.g. Clear out all of your unwanted items in one day. Make sure that you are finished by the end of the day (and reward yourself in some way (positive reinforcement) when you are completed).
5. Meditation - Although you may not feel motivated from meditation, I have found that it helps organize thoughts and improve focus on what needs to be done. Focus can go a very long way when it comes to productivity/motivation.
Obviously things like caffeine (red bulls / expressos) are going to increase your mental excitement/energy, but they will not necessarily help to motivate you to get a specific task done.