Mnemosyne,
I'm so glad to hear you are considering going raw.
There is another
thread on raw food.
I would say raw is the extreme opposite of where you are at now. I've been raw for 5 weeks, but I've been transitioning from the Standard American Diet gradually for 8 years.
If you are brave and willing and able to invest in the proper equipment you may want to consider starting with a liquid cleanse. But be prepared for detox symptoms. I don't really have much experience in this area.
If you want to transition more slowly, I would suggest introducing healthy foods that you like one by one into your diet. When you do that pay close attention to how what you eat makes you feel as long as 4 hours after you eat it. You will begin to see how many variables there are that effect how you feel. Hang in there.
The important thing is to become more in tune with your body. One thing you can try that may seem kind of gross but I think it's a great excercise is to try chewing your food 30 to 50 times before swallowing it. Pay attention to how it tastes. Foods that are bad for you will start to taste bad quickly. Foods that are good for may still taste good after 50 chews.
I think raw food is actually the tastiest food there is. The beauty of raw food is very subtle but much deeper than the attraction of junk food.
Do you like smoothies? That might be a good place to start...