I've worked for years to figure out how good rice is made in restaurants. I like it in some restaurants, hate it in others (and I tend not to go back). I'm still working on it, but here's where I am right now. Don't over-do it with spices and aromates when the rice is only a back-drop to what you're really serving.
See also my lime-cilantro rice recipe, if you like that sort of thing.
The essence of rice as a side dish in Mexican cooking is pilaf, which is to say in my opinion that it's a) washed clear of excess starch (as a dust or detritus on the grains that would cause them to stick together upon being cooked), b) fried in oil before the addition of any liquid and c) cooked in a savory liquid like chicken stock.
You can put other stuff into the rice; I've seen it done often, but I would tend to refer to the product as arroz y cosas, and find it a case of gilding the lily: this is an accompaniment to what's your real dish (enchiladas, chili rellenos, tamales, etc.) and not a principal course. It will a) not please everyone and b) detract from the main course.
| 3 cups | rice |
| 6 cups | water, piping hot |
| — | oil |
| 1-2 tablets | caldo de tomate |
| 1 tablet | caldo de pollo very optional |
| 1 cup | finely chopped white onion |
| — | kosher salt |
1. Rinse rice until water runs clear. Drain as well as possible in collander.
2. Sauté onion with the salt until translucent, but not browned; reserve.
3. Place oil in hot pan (big enough to hold rice and liquid ingredients—it needs a good lid that fits reasonably tight).
4. Add rice to pan and stir in oil until most of the rice becomes pearly white. Add in caldo tablets, break them up and add onion; stir into rice.
This is the single most important step in cooking rice that will ressemble what you get at the restaurant: you cannot cook the rice in an oriental-style rice cooker and you cannot boil it.
5. Meanwhile heat liquid to very hot in the microwave.
6. Carefully pour the boiling water into the hot rice. Bring back to a boil, then cover and don't lift the lid thereafter. You can set a timer and put this into a 350° oven instead to avoid burning the bottom. This allows you to turn your attention mindlessly to other matters, but you'll need to figure twice as long to cook.
7. Remove lid, fluff rice and serve.