Research, research , research! I cannot say enough about it! Research helps, but make sure your research is reliable. One book that I think that everyone should have (I'll admit to having it), is Eat This, Not That. It gives you an eye opening idea of how the food is and what to avoid.
Cut down on the sugar and salt intake, this includes those nasty dietary sugars. Sugar is bad for you, and dietary sugar is even worse! Salt retains water, which makes you gain weight. Please remember, you do need salt and sugar in your diet, you just need to cut down on it.
Cut out the soda, even if it is diet. It contains high amount of sugar and, if you think that diet soda is better, research has proven that it is actually worse than regular sugar. Instead, opt for milk, tea, or water. As for juice, look for juice that is 100% pure orange or apple juice. Don't do for anything that is a mix. Chances are, it will be higher in sugar.
Add more variety. As they say, variety is the spice of life! This is a good way in order to get a lot of your nutrients in.
When at a store, park the farthest away from the door that you possibly can. Also, if there is a place nearby, consider walking instead of driving.
I have more, I just need to figure them out.