Difference between "to hit" and "to strike"?

There is no real difference between the two.

To strike something = To hit something

The only difference is the 'feel'. When someone 'strikes' (Martial arts, strike the ball [soccer]) it is more deliberate and concentrated. So you are going to strike something (it's a deliberate choice). 

Whereas 'to hit' feels like it could be applied to anything, (I hit him, I hit the pillow in frustration etc.). 

Personally i don't see any difference, 'hit' is used (In my opinion) more often, but both are natural.

Hope this helps