I think people who are anxious have a harder time getting to that relaxed state meditation provides.
www.yogajournal.com has some interesting articles on meditation. They have a newsletter with a daily yoga insight which can provides some relaxations tip.
I know when I meditate I can block thoughts but I think it indicates that I am tense. If I were relaxed thoughts should be going through my mind.
Here is an interesting link on relaxation where the article states thoughts should be going through your mind and it’s what you do when them that makes it meditating.
Here is a link to the article:http://www.yogajournal.com/practice/587
I think what has made meditating difficult for me is that it means sitting still for a period of time when you are tense.
Now when I meditate I start it with stretching and breathing exercises to get me relaxed. I start it off with an autogenic relaxation because autogenics does make me feel more relaxed. Then I meditate. I find my preferred method changes from breath counting to mantra-I do whatever feels good to me. I also do it for as long as it feels good. Usually, it is still only about five minutes.
I do the meditation when I most alert which is for me in the morning so I don't fall asleep.