This is a really good thread Jade!
Anyways, while my diet is far from perfect, I do try to eat clean animals and avoid pork and shellfish. The reason is because of the risks of eating pork and shellfish, especially if they are not cooked properly and the fact that shellfish tend to be "bottom feeders", not exactly the healthiest thing!
Being someone who eats out (no time for cooking on my end) often, I find by making switches to what I get makes all the difference. If you go to a Mexican place, usually they have an option to make a salad out of your favorite burrito or taco (might I suggest Baja Fresh's Diablo Burrito Bare Style? Very good!). If you go to McDonald's, opt for smaller portions, instead of getting a "value meal", go for the $1 items, such as a small fry (as opposed to a medium), Mcchicken, or four piece nugget.
Do the same for your beverages too. If you go to Starbucks or Dunking Donuts, opt for iced coffee (usually not fattening) with skim/non-fat milk (soy milk if you want, but soy makes you gain weight, especially if you have thyroid issues). Don't go for the frozen, slushed drunks and definitely avoid the pastries and bagels. If you have to drink soda (confession- I do and love it!), drink regular soda and NOT diet soda. Diet soda has no calories, so it basically bloats you and gives you no energy to burn off. And of course drink water (not the eight glasses a day thing, but do make sure you have some each day).
I go to the gym too, 3-4 times a week if I can, the best thing to do is cardio for 30 minutes. Use the elliptical instead of the treadmill, the elliptical works your arms, buttocks and legs and you burn off more energy than you do running (and it's less risky). Also use machines, don't overdo the weight you lift but just enough, I'd go with 2-3 reps of at least 7-15 (depending how many you can do). And do not overdo yourself, because that only makes it harder for your body to get used to exercise and the pain will discourage you.