I agree with the others that have said to start slow. I dieted in the past, and I just got frustrated and quit. Prior to starting my diet, I was drinking 1000-1500 in Mt Dew/Pepsi alone. My first goal was to give up the soda. I did that in mid-December. It was VERY difficult for me to do, since I work for PEPSI!! But now I'm drinking Aquafina bottled water throughout the day, adding a cyrstal light lemonade to it when I want a little flavor. After the initial headaches from lack of caffeine faded, it was easy!!
My next step was to ditch the fast food. I'm usually crazy busy at work, and I never packed a lunch. Now I bring breakfast and lunch with me to work! Once a week, I will allow myself to go out for a salad, just to get out of the office.
My last step was to get a routine of daily exersize going and cut my calorie intake/eat better, healthier foods. Chicken is my favorite food, and it was easy to switch from fried chicken over to grilling skinless/boneless chicken. Jello, a favorit treat of mine, doesn't taste all that different in the sugarless variety. Light popcorn actually tastes BETTER than movie butter popcorn, now that I've tried it.
Overall it hasn't been that hard. If I get a craving, I'll usually give into it, but watch my portions. I've lost 21 lbs so far, and I'm down 3 pants sizes - from a 16 to a 10! I have customers that come into my work about once a month & they have all noticed my weight loss and compliment me. That gives me the fuel I need to keep it going!!