HAHA well I know what you mean, sometimes doing that barely noticeable hand touch on the shoulder or the girly flick of hair stuff doesn't really show your crush you like him.
Some guys can easily figure out these signs but some may be more hesitant to pick them up as 'flirting' or the girl 'liking' them.
If you really want him to obviously know you like him it really depends personally what your situation is. Is it the fact that you hang out with him? Maybe in same friendship group ?
You talk to him frequently already? you talk to him mostly online not as much in real life? Or even he's best friends with you but you suddenly start having different feelings about him?
Whichever one it is , being obvious about liking him is easier than trying to hide it, well thats me personally :P
So I suggest you act 'More' friendly maybe compliments , like you look cute today or you do something to your hair it suits you so much, becoming closer , maybe lingering more when you talk , caring more about him or paying more attention eg. Hey i saw you at soccer practice your so good I can't even kick a ball properly :P
Show that you pay attention , or a easier way to let a guy know is your friends telling him or his friends you like him.