Breath meditation is the basic meditation behind all others, and so can be considered the most powerful. Even trances can be truncated in time through its use. Breath meditation is the oldest of all meditations; the first and biggest discovery of mankind. Likely developed by an ancient archetypal "Sith" who was later killed, and that art perverted into the archtypal "Jedi" orders, like the Shamans or the Samurai. There are two main types, both of which are Taoist:
Type One: Counted Breaths
-Sit "Indian style", with your legs crossed under you. Then rest your arms on your legs. Now, close your eyes This is called the Six Point Position, as seen below.
Type Two: Nasal Sensation
-Sit in the six-point position.
-Breath in through your nose, noticing the sensation of air moving in through your nostrils.
-Breath out, once again noticing the sensation. Focus on nothing elese, and continue this slow, steady beathing until calm or when desired.
These meditations are the base of all others. However, there is another basic type, developed by Lord Draconious, that should be known.
Type Three: Draconian Trance Meditation
-Sit in the six-point position; or lay down... just don't fall asleep. Choose a quiet place.
-Now, notice a steady sound; perhaps it's your heart or breathing, or maybe it's your watch.
-Choose one of these steady rythmic sounds, and focus on it.
-The sound will become very loud. Hold your breath for periods of times, but do not hold it to the point of uncomfort.
-The deeper trance you are in, the longer your breath can be held. The longer you meditate this way the better.
Here are a list of useful meditations sites. I recomend checking them out: