If you have a burger, order it with lettuce, tomato and other veggies you might like, then remove
the bun, or
at least 1/2 of it and eat the meat and veggies with a fork.
You can opt for restaurants with salad bar, or those that provide a good sized salad with each meal and load up on salad before your meal comes, so you aren't so hungry. Be sure to use a low cal dressing, vinegar, lemon juice, etc.
Make sure you drink water or unsweetened tea or coffee vs sodas.