Woks are ubiquitous throughout Asia. In Thailand, I ate many many meals prepared in a wok, including literally hundreds of plates of pad thai. Like much street food throughout Asia, pad thai is prepared in approximately one minute in a wok which, during busy times, almost never leaves the gas flame that provides the heat for cooking.
Those street woks are so well seasoned that they do not require any washing; after each round of food prep, the cook simply throws a bit of water into the wok, swirls it around, throws it away, and moves right on to the next round. They place the wok on the heat to evaporate the remaining water, then pour in a little oil and get to it.
For you and me, it can be difficult to achieve and maintain this level of seasoning for our woks. If you buy a wok that is completely unseasoned, you will need to season it. Wipe the pan inside and out with a little light vegetable oil and heat it in a medium oven for about half an hour. Allow it to cool and repeat the process several times to build up a good coating. A good coating on a well-seasoned wok will discourage food from sticking and make the wok much easier to clean. Woks should be washed by being wiped with a soft wet cloth; only use a mild soap if absolutely necessary. If your wok is made of cast iron, it should be dried immediately after washing to prevent rusting. Over time a wok will blacken, a sign that it has been used well. It is said that the blacker the wok the better the cook.
The home cook faces a number of problems in achieving this perfect wok coating. If any food sticks to the wok, it is difficult to avoid scrubbing to remove it, which compromises the coating so carefully built up. A careless roommate can mistreat your wok, ruining all your hard work in maintaining the wok's coating. But the most serious problem I faced is that acidic foods like lime juice, chili garlic sauce, or tamarind eat away at the coating, exposing the raw metal underneath. As the Thai food I prepare so often tends to have sauces made from these delicious acidic ingredients, I found it impossible to maintain a steel wok in optimum condition.
Therefore, I now use a non-stick, teflon-coated wok. One of the main advantages of a non-stick wok is, of course, that nothing sticks to it. It's a breeze to clean, and doesn't require much special care. As with any non-stick cookware, you should not expose it to very high heat; I generally stir-fry at medium high. In addition, don't use metal utensils to stir things in your non-stick cookware, as they will scratch the surface. Don't scrub non-stick vessels with an abrasive scrubber, either, for the same reason. For steaming in my wok, I use big bamboo steamers set on the top of the wok. I use my wok almost every day, and even though it's a cheap one I bought in my local Chinatown, it will serve me for several years before I have to replace it.
Incidentally, I use a wok with a flat, as opposed to a curved, bottom. This allows me to place my wok directly on the burner of my electric stove so that I have much better control over temperature than if I were to use a wok ring. If you must use a ring, put the wider side facing up and the narrower side on the burner; this will send more heat to the bottom of the wok, where you want it.