Keep the junk out of the house. It's very easy for motivation to decline. When you're feeling weak and the junk is in reach, you're likely to cave. If its not in the house, you'll learn to deal with cravings and realize they too shall pass.
Take a multi vitamin, especially when dieting. It can be very difficult to get all the recommended vitamins and minerals when you are restricting calories.
Grill, grill, grill!
When I'm really hungry or I want to eat because I'm bored or frustrated, I have a tendency to ear what I shouldn't - i.e - icecream, cookies, etc. If I don't have them in the house, I can't reach for them. Clean out your cupboards and fridge. If they are not in the house, you can't eat them!
I was having a hard time with exercise so I decided to only make a short term goal. My goal was to walk for one hour on Friday, Saturday and Sunday and I did. It didn't seem so horrible as committing to getting on the treadmill 4 times per week every week. Just one day at a time!