I find that great motivation can come from a pair of jeans. Any pair you are working towards fitting in. Put them on once a week even if they don't fit. If they don't tell yourself, "This is my goal, this is what I'm working towards". If they seem to fit even slightly better than the last time you tried them on, then just the excitement alone should keep you going strong to feel great wiggling the rest of the way into those jeans!
I find it so motivating to read the diaries and success stories (and before and after pics) of people who have done the same diet as me. It makes me realise that it isn't impossible and it can be done.