Do ...

Reduce the amount of meat in your meal.

Order more vegetable dishes or dishes that have a high proportion of vegetables, such as Beef with Broccoli.

Order steamed rice. Filling up on steamed rice will mean you eat less of the other dishes.  Another reason to eat rice is that it is a complex carbohydrate. Besides being low in calories, complex carbohydrates boost the metabolism.

Stick to Cantonese cuisine if possible.  Cantonese dishes tend to be lighter and use fresh ingredients. 

Let the restaurant know your dietary needs so that they can accommodate you if possible.   

Cut down on sodium the day you are planning to order Chinese food.  Most Chinese restaurant dishes have a very high sodium count.

Don't...

Order deep-fried dishes such as Kung Pao Chicken, General Tso's Chicken, Mu Shu Pork, or even Egg Rolls.

Order fried rice. The eggs in fried rice mean a high cholesterol count.

Order dishes with nuts (another reason to say no to Kung Pao and General Tso's Chicken).  In moderation, nuts are quite healthy, and a staple in most Asian diets. In fact, recent studies indicate that peanuts (which is not really a nut at all, but a legume) may even lower cholesterol. But take-outs use way too much. Unless you can persuade them to reduce the amount, steer clear of all the tempting chicken and nut combinations.

Order dishes with heavy sauces. 

One final tip: when searching for a good take-out, my normal strategy is to find a Chinese restaurant that offers take-out and then dine there one evening  preferably during their peak busy hours. If the food is good, then I'll order takeout from them.