Welcome Diana!! I think that you'll find this site so helpful - I know that I do!! Some things that have helped me are finding a workout that's convenient to do around my schedule that I like and also finding healthy foods that I like and keeping them in the house. I have to keep all junk out of my house and I prefer to workout at home to workout tapes. It works well for me but you have to find what works for you.
Also, don't be too hard on yourself if you slip up a little -- that's life -- accept your mistakes and move on
Good luck! you can do it!