make sure the needle you are using is the correct size/type for the thread you are using- treat with thread heaven or bees wax, and check the label ensuring it does in fact say 'hand quilting' on it- most thread companies carry a vast assortment of threads- just because it says Gutterman on the label does not necessarily mean it's for hand quilting-
cut your lengths about 18", with longer lengths you often spend more time untangling than actually stitching--the longer the length the more (wear) on the thread- the sooner you will have problems- breaking, fraying, tangling