I use top side meat if I can. Cut along the grain in 1 wide cuts. Trim any fatty looking bits.
Marinated in salt (wee bit as salt will be pulled from the meat), pepper, loads of vinegar (making sure all meat is covered), a good hand full of South African biltong spice. Leave it for 24hrs, turning several times during this period. The vinegar will like cook it.
I have a fan box that has a 1 hole matrix and all sides, I hang them for 4-5 days. If you wish to freeze them I cut that down to about 3 days.