Your question is a relevant one because not being able to meditate is a common problem. Being unable to meditate is not the matter of concern. But the reason behind your inability might be. We need to understand the reason in order to succeed in anything. Be it meditation, or any other work, you need patience for it.
Any child, who is not able to do some work is advised to practice constantly and after sometime, he acquires it as a habit. Hurdles on a walk would come for some days, but eventually the grass on the path would make the way for you. Similarly, your mind is like a grassy path, grass being your thoughts which distract you.
For meditating without any distractions, you need to eliminate all the thoughts from your mind, concentrating on just one thought. After some time you will find yourself able to eliminate that one single thought as well, achieving the state of complete thoughtlessness, just like when you are asleep.
But as you know, sleep is just not thoughtless, it’s effortless too. Hence, constant practice will make you reach this state of complete thoughtlessness effortlessly. This is the reason meditation is known as “yoga nidra” or “jagrit nidra”, meaning “yoga sleep” or “awake sleep”.