I never really knew what to do with the hand motions for memorizing verses so I instead just read them very dramatically sometimes extremely and we sort of act them out. This is not of course to bring disrespect and we do not always read them this way when we are memorizing. My kids really do well with this and memorize very quickly this way and it tends to make it stick for them. I believe this is the point of the hand motions but if you are hand motion challenged this is just another option to get the job done. 
Another thing we do which ofter HOD prompts anyway is really go deep into what is the meaning of the verse and read a few commentaries and different versions of the verse. I think that helps as well. Anyway just wanted to put it out there if you are challenged like I am to come up with hand motions.
The more dramatic I get the easier they remember them and it makes it fun for them. They still seem to have a respect for the Word and understand this is just something we do to remember it so we can hide it in our hearts.Thought I would just share.