When I first started on the Jedi path, one of my main concerns was how to meditate and clear my head. That's one of the things you always hear about with meditation. "Just sit there and clear your head." Well, I'm sure everyone has learned how difficult that can be. If we could just sit and clear our head, we wouldn't need much meditative practice, now would we?
It wasn't until 3 years into my path that I finally received the insight required to gain control of my mind. The Buddhists at my university offer classes where they bring up the local master from Houston and they address the basics of Buddhism, including meditation. I only went to one class, but it gave me all the insight I needed at that point in my life. I'll do my best to pass that insight onto you so you may benefit as I did.
If you're anything like me, sitting in meditation involved a slew of random thoughts, and one song that was stuck in there from who knows when! I would sit and try to let them go, tell them to leave, all sorts of things, but it never worked. Apparently I was going about it all wrong! By focusing on the thoughts, I kept them with me, no matter what I did. I put energy towards them, and anything we put energy towards we keep to us. So while I wanted to release them, what I was experiencing was these extraneous thoughts distracting me. I kept focusing on this distraction which kept the experience of distraction with me. However, what I wish to experience is focus, so that is what I need to put energy towards. The monk described it in this manner.
Say you're holding a coffee cup in your hand. There's nothing inherently wrong with holding a coffee cup, but you would rather hold the beautiful rock on the table. Now pretend that you don't know how to put down something. I know it can be a bit of a stretch, but just pretend. After all, this is only an analogy. :-)
Since you don't know how to put down the cup, you try all sorts of things, but no matter what the cup stays in your hand. This is what I had tried for years, and many others I'm sure. But what if we did something else.
We already know how to pick things up, as evident by the cup in our hand. So instead of focusing on what we don't want, the cup, let's focus on what we do want, the rock. Focusing on the rock, we reach down and pick it up. Now you're holding a rock in your hand. In order to do that, you had to release the cup in some way. It doesn't even matter how, just that you did. This is how we release our thoughts.
When we meditate, there is something to focus on, usually breathing or counting. When we notice an extraneous thought, don't focus on the thought. Instead, return our focus to the counting or breathing. Keep focusing, and before you know it the thought will have left your focus without you actively removing it! For me this was a breakthrough, because though I had many, many random thoughts, I could return my focus to breathing and find that quiet center again. Yes, you will probably have to do this all the time when you meditate, but in time you will see results in how long you go without extra thoughts.
This idea can be applied elsewhere in your life also. Do you have a song in your head that you absolutely hate? Find a song that you love and sing that in your head until it overwhelms the original song. Is there something bothering you? Think of something else. Focus on something that is more useful to you. The applications to your life are limitless and can help you gain control over the ever wandering mind.
Best of luck in your practice.