Meditation is a pretty vague term. There are a number of practices or things to do that get put under the heading of “meditation” usually.
There is shamatha-vipashyana, or mindfulness-awareness. This is also called mindfulness meditation. In Tibetan it’s called “shinay” or “shinay-lhakthong.” This is the kind most people learn, if they learn a technique. It’s really good, and pretty simple.
There is contemplation. This involves going over a word or phrase in your mind, and thinking about it. It’s like thinking meditation.
There is visualization. I haven’t learned much about this yet. It’s considered an advanced practice. I won’t be teaching this for a while (considering I haven’t even learned it!) and probably won’t post anything here about it.
There are more advanced techniques, involving yoga. There is what are called “mahamudra” and “dzogchen.” These are generally considered, in Tibetan Buddhism, the highest, most advanced practices.
Then there’s study. Technically it’s not meditation, but they say it’s good to study too. This could involve reading books, going to classes (!), discussing this stuff with other practitioners, and so forth.