-Sit comfortably, either on a chair or on the floor. Close your eyes.
-Lengthen your spine up towards the ceiling, as if a string were attached to the crown of your head.
-Relax your shoulders by rolling them down your back.
-Breathe slowly and deeply through the nose. Fill your lungs from the bottom up. Focus on feeling your abdomen push out, then the middle of your chest, and finally your upper ribs.
-Breathe out through your mouth in the reverse order - compressing your chest from the top down (ribs, solar plexus, lower abdomen).
Repeat this a few times, breathing slowly, deeply and mindfully. To breathe mindfully means to focus on the act of of breathing, and how it feels inside of you. Notice the temperature and moistness of the air in your nose, the ribs expanding, the shoulder blades being stretched, the sound the breath makes...
The idea is to calm your body with deep breathing, and calm your mind by focusing solely on the breathing. Try to allow your muscles to relax and be stretched by the breaths (but keep the back straight). Your mind should be empty at the end of this.
It may take a few practices before you're able to completely clear your mind. You might consider taking free meditation workshops or yoga classes offered by your community centre.
As the URL (and title) implies, it provides you with a good starting point. I'd floundered for quite a while reading up on theory, which is nice but has nothing on actual practice.
In particular, he linked (and now, so will I) to the online text of Mindfulness In Plain English at http://www.urbandharma.org/udharma4/mpe.html, which is both pragmatic and convincing.
Those two links finally got me started on the meditation practice I'd intended to try for years, and I've stuck to it without breaks longer than a day or two.
You can do simple meditation by just reading a book about it and following through. Although high-level meditation should only be learned from a master, I would say that the advices that you have in this thread are pretty efficient. Just don't try do to anything else, like meditate with music or any other New Age or whatever. Meditation is very simple, which is why it is hard at the beginning, but it is also very profound and very powerful.
One of the keys to meditation (and to most of Oriental arts) is consistent practice. If you can find supervision it is better, but you can go a long way just by practicing consistently and correctly.
