Is caffeine the thorn in your side? Are you starting to feel like you just can't live without it? Well, you can! Caffeine is a drug, and like any drug, in order to free yourself from addiction, you have to be committed to your plan of action, and be ready for the pain and frustration of withdrawal. The key to quitting is the knowledge that things will get worse before they get better. But, once they get better, they will stay better.

 
Write down your reasons for quitting, such as:

tooth decay

weakened bones

addiction/dependence

a cycle of hyperactivity and/or inability to focus, followed by a subsequent "crash"

disrupted sleep habits

may interfere with weight loss

financial costs to support caffeine purchases

pregnancy and nursing

Put this list somewhere that you can see it regularly, like on your mirror or work desk (or both). It will help keep you motivated.
Realize that quitting will require a significant effort on your part. Erase any idea in your mind that quitting caffeine will be easy, or else you'll be in for a big surprise. Expect it to be one of the most difficult things in the world, and you'll be ready to give it your greatest effort.
Prepare for the withdrawal symptoms, which can begin within hours of your last caffeine fix, and may last for up to two weeks:

headache

fatigue

difficulty concentrating

flu-like symptoms

Sit down and calculate how much time and money you actually spend on caffeine.

Think of other things you could do with that time and money. Buy and read the newspaper? Pursue a hobby? Save money for an iPod? Start a trust fund for a child you love? Find something that's exciting and fulfilling, and think of it as your reward.

Don't go it alone. Find someone to quit with you. If you can't find that kind of support, promise to someone whom you love and respect that you will quit caffeine.
Thus, consuming caffeine in any form will make you break your promise, and this will provide you with another incentive to stay on the wagon.

Reduce your intake gradually.

You can set a schedule for yourself, such as "3 cans a day in the first week; 2 cans a day in the second week; 1 can a day in third week; and none in the fourth week." Start replacing your caffeinated beverages with the decaf versions. Consider switching slowly to water or teas as a substitute.

Allocate your caffeine money in the beginning of the week, so that if you over-consume it in the beginning of the week, you will have nothing to fall back onto in the end of the week. If you allocate less and less caffeine money as you go on, you will gradually reduce your intake.

Different people use different ways of quitting. What works for one person may not work for another. Try these steps in any order to see what works best for you.

Kicking it in one clear cut may work well for some, even with the symptoms. Feeling the headache and fatigue can actually demonstrate just what the caffeine is doing to your system. It does also give some an important sense of accomplishment - since some people may not notice the difference when giving it up gradually.

Get yourself a replacement drink, it could be water, hot chocholate, decaf - just something to get when the urge for a cup sneaks in.

There is caffeine in lots of drinks, not just the dark ones like coffee and cola.
Stay clear of energy drinks and be careful with tea. You should make a habit of checking out the ingredients of what you drink so you dont sabotage your efforts.