Raw foods are very important to maintaing good health because they contain substances(antioxidants and phytonutriets) that are essential to preventing certain diseases. For example, broccoli and tomatoes both have phytonutritients in them that assist in preventing cancer. These vital nutrients are often lost in the cooking process, and the food is, if it is over cooked, lackluster because it really does not have any nutritional value.
Raw foods in addition to phytonutritents contain vitamins and minerals that are destroyed in the process of cooking. Important vitamins such as vitamin A, E, C, K are all sensitive to the high heats they are often exposed to. But once you take heat out of the picture, you are left with vitamin-filled foods that will aid you in many of your health problems.You may even find that once you begin to juice and consume more raw foods, issuess such as sleep disruption and pain, to smaller issues like acne and skin rejuvanation, and most certainly weight loss can be assited by these necessary vitamins.
So, it is important to consume as many raw, nutrient-dense foods as often as possible. Though going totally raw is something that would probably be most beneficial, most of us don't want to do that--me included. To remedy that, going totally raw is not a necessity; however, eating more fresh salads and juiced vegetables/fruits, would be a great way to start! I plan on starting my own raw food diet sometime this summer, so I'll keep you posted on that. If you have decided to go raw, you will need to know a few things.
If you want to do all your food preparation with raw foods, there are somethings that are not necessarily a must, but it would be helpful to have them. Purchasing a dehydrator and a good quality food processor/juicer. Without these tools you can certainly be a raw foodie, but these things make the food a lot more similar to the kinds of foods you used to eat, except they have the nutrtional value that would have been lost during the cooking process.
What makes a good quality food processor/juicer. Well, for one thing, it has to have low RPM (meaning it has to be slower machine) because the higher speed juicers frequently get too hot and destroy enzymes necessary for digestion of the food. This is particularly true for juicing carrots and apples. Food processors/juicers tend to be on the expensive side; so, it isn't for those who can't afford it (quality juicers run anywhere from $235-$2,000).
Finally, the best foods for going raw would be beans, alfalfa, milk (raw milk is a must!), nuts, broccoli, leafy vegetables, carrots, apples, watermelons, just about any fruit or vegetable!
Note: if it isn't apparent, you shouldn't try to juice bananas (duh! right?). Seems like a stupid precaution, but it is surprising how often such mistakes can be made.
Those are the basics. There is a wealth of information on this topic on google as well as here.