The main important things is that it is something that they are comfortable with. One of the simplest things to concentrate on is your breathing. In fact, most meditation techniques start out this way so that your muscles will be relaxed and your mind and body become one. Sometimes, staring into an object can produce similar results.
The best part about is that it doesn’t have to be physical because when you are trying to get some sleep. you can focus on a cloud or the open ocean. If thinking about an object is not your thing, then you can try to focus on sounds or words.
This is the reason that there are CD’s that you can buy which play calming music or with someone in the background talking to your meditation relaxation session.