There are many forms of meditation, and many ways to achieve a meditative state. Here I will instruct you on one way to achieve a revitalizing trance meditation state.
Pick some songs or a CD to listen to. Something with a steady beat is best for this method. Nothing too mellow. I suggest trance, dance or techno. Some rock can have a steady enough beat. You'll want a full CD, or about 30-50 minutes of music.
Find a spot where you will not be interrupted. A closed bedroom or the back corner of the yard can be good, wherever you feel comfortable. Make sure you will have some time with no distractions like phones, television or children.
Relax. Either recline or lie down. Make sure you are very comfortable. You don't want to be shifting around a lot.
Turn on your music. During the first track, try to focus on the beat, and remove distracting thoughts from your head. You can use a variety of visualizations to achieve this. You may imagine a volume knob that you can slowly turn down until random thoughts have quieted, or perhaps envision a blackboard from which you can erase thoughts and distractions.
During the second track, you will either continue clearing distractions, or move on. If you feel that your mind is clear enough, begin placing images into your mind. Use the beat to inspire your vision. You might picture flowers blooming to the beat, or paints swirling on a canvas, or whatever you like. Pick something that you can allow to shift and flow.
As the songs continue, keep these shifting images in your mind. Allow your body to relax, and you mind to create visions as it chooses. Only change the vision if something distracting creeps in, at which point you will repeat step 4 until it has left your mind.
If your mind seems to go blank, or your heartbeat changes to match the beat, this is fine. It's a good state of relaxation and mental clarity.
With practice, you will be able to achieve a wonderfully meditative state. You body will feel light, you may experience a slight tingling sensation all over, and when you come out of this state, you will feel energized and refreshed. Later on, if you choose, you may use this state to focus on visions of healing your body, gaining wealth, self-improvement, or any goal you desire.