There's really nothing wrong with adding cheese to your meals. Try to select low fat or fat free cheese, or use the regular cheese sparingly. Dairy is a great food group that supplies quality protein and other nutrients.
When you are putting your meals together, just try to focus on incorporating a variety of healthy food items from each food group. Pretty much all fruits and vegetables are great options. Choose whole fruit over dried fruit or fruit juice. Pick lean protein foods like lean cuts of chicken, beef, seafood, eggs, turkey, tofu, protein powder. Try to make most of your grains whole, like whole grain bread/cereal, brown rice, wheat pasta, oatmeal. Again, low-fat/fat-free will be best for dairy, such as milk, cheese, yogurt.
A quick (if generic) example is a meal of grilled skinless boneless chicken breast, mixed vegetables, brown rice, an apple, and a low fat cheese stick. Portion size is also a big component, since you can still easily over eat healthy foods.