I've recently taken up goju-ryu karate. In sparring, I'm often matched up with someone significantly taller than myself (by a foot or more), and find that I have trouble finding openings due to their relatively easy access to striking (oftentimes hammer strike) at my head when I close the distance.
It may simply be due to my having less experience, but are there any strategies I can use to close the distance without making it easy for my taller opponents to strike my head?