Are you going to class? I can't stick to it for long on my own. I need face to face support as well as this forum.
Take a favourite piece of clothing, try it on and hang it on the front of your wardrobe to remind you of why you want to do this. Keep a diary, PLAN! Don't buy your red light foods! If you have a partner and they eat them, get them to hide them away! (work or the car boot is best!) and they mustn't ask you if you want any!
I get OH to take a photo of me each month so I have a record of the changes, and yes all the excellent tips everyone else has given you. But YOU really must want to do it, there is no magic wand.