Honestly, you don't have to do a lot. There's just a few things I would say that would help you
1. Try to cut down on sodas and sugar - this is easier than you would think, just drink water and sports drinks and say no to candies and chocolates (not to say you can't have them any more)
2. Eat somewhat healthy - everyone usually eats enough grains, so just worry about getting a few fruits and vegetables each day
3. Exercise 1-2 times a week, depending on how hard you work out. If you want different exercises that don't require any weights, I wrote a few Hubs about it if you want to check it out.
If you plan on losing weight, then cardio and swimming is your best bet (along with healthy eating).
But you do need your fats. My trainer used to tell me that I get one cheat day - one day of the week to eat a bowl of ice-cream, a box of sweets, etc.
It is not too difficult, you just have to treat it as a game. I always see how much candy I can refuse before I take some. It makes it a lot easier for me to eat healthy