I came across this somewhere and found it very true...! :) lol. I'm sure some of us subconsciously employ some of these tactics while ordering cai fan.. except the ones in blue and orange, which I felt might not always work. haha..
Guide to ordering Economical Rice
Visit the stall near the end of lunch/dinner time. Sure, some of the dishes may be sold out, but there will also be plenty of other dishes still available. Since the stall owner can't keep the dishes until the next lunch/dinner time, it is in his interest to give away larger portions so that he won't need to deal with leftovers later.
Get your guy colleague to order for you. This only applies to girls. Stall owners tend to give a smaller portion to girls compared to guys. However, they charge the same price for both. So it is more value for money for a guy to place the order on behalf of the girl so as to receive a larger portion.
Ask for 'more rice' instead of 'add rice'. Most stall owners will interpret 'more rice' as a larger scoop of rice which will result in more rice. This is generally free. However, 'add rice' entails adding a second scoop of rice to the first, and this generally costs additional money.
Make sure the stall owner has space to serve. In many mixed vege stalls, there are usually two or more people serving dishes as the same time. When you are ordering, make sure to order dishes that are near the person serving you so that he won't have to stretch over his co-worker to reach your dish. If he is stretching to reach your dish, he probably won't give you more than usual serving since it is that much of a hassle.
Order the meat first. This is to create a good impression with the stall owner. By ordering the meat first, your are signaling to the stall owner that you will not be ordering the cheapest items on the menu. This puts the owner in a better mood, so he may give you a larger serving.
Order 1 dish at a time and wait until he finished serving. Point to your first dish, then wait until the stall owner finish serving it before pointing to the next dish. Do not rush him. Often, the stall owner needs time to gauge the portion of food to serve. If you give him sufficient time, it is likely that he will give you a larger than standard portion. Hurrying him results in less than standard portions.
Pause in between ordering dishes. Pretend to ponder in between dishes. This gives more time for the stall owner to serve your previous dish which likely will result in a larger portion. When he is finished and noticed that you are still pondering over your next order, he may feel bored and add a few more slices of your previous dish while waiting for you to make your next choice. Order the same dish twice. Use this technique very sparingly. After order a dish, pretend to look distracted and point to the same dish again. The stall owner will likely tell you that he has already served that dish. However, occasionally, he may instinctively go through the motion of serving the dish again and make your portion slightly larger, all for the same price. Order dishes that are about to run out. It takes practice to estimate, but it is worth picking dishes that are left with about 1.5 to 2 portions. Chances are, that if there is only about 1.5 to 2 portions of the dish left, the stall owner will think 'what-the-heck' and just give you everything. The good is that you get extra servings, the bad is that sauces right at the bottom of the tray are very salty.
Order vege dishes that contain meat sauces. Some vege dishes have some meat in it to bring out the additional flavour. But it is sold at the price of vege becos the meat is usually in small amounts and only present in the sauce. Tofu dishes are an example of such. By ordering such dishes, you are getting some serving of meat for the price of vege. Nice.
Do not order meat dishes that contain vegetables. These dishes count as meat but is usual half served with vegetables. It is very not worthwhile, do not order it. An example is the stir fried venison with leek. Go for fully meat dishes instead.
Ask for curry sauce. Many a time, when you ask for curry sauce, some other ingredients in the curry sauce will find its way onto your rice, such as small pieces of chicken or potato. Cabbage curry sauce will probably bring you some cabbages and longbeans. And it's free.
Ask for meat sauces. As mentioned earlier, some sauces are cooked with minced meat. It is near impossible to separate the mince meat from the sauce. So if you ask for meat sauces, you will definitely receive some serving of meat with it. And it's free.
Become a regular customer. Talk to the stall owner on occasions. With good rapport, the stall owner will recognize you as a regular customer and will naturally give you extra servings the next time you visit.