Start small.
Like if your walking with a girl in the hall and then enter a classroom, place your hand on her lower back and guide her in first, with you following behind. This should feel 100% natural to do.
Or when you wish to greet a girl you know but her back is turned to you, walk up to her and place both your hands on her shoulders followed by a "hey whatsup"
You ask for a penceil in class, touch her hand slightly as you take it from her.
Small things like that is what you need to start with. This is something you need to practice, get confortable with, and get down, because kino displays many attractive attrubutes to a girl.
Its a must.
Start doing these things to the girls you are most confortable with.
Oh and another thing, touching shouldnt be seen as weird or unnatural. Society discurages it wrongfully because of a few weirdos out there. But its human nature to touch and feel. We may depend on sight the most, we are very visual creatures, but touching goes deeper than sight can go, it makes a subconcsious bond with the person.