Lust is any intense desire or craving for self gratification and excitement (wikipedia).
Lust is in general thought to be associated only with sex but thats a very limited viewpoint. The definition above is generic enough to include lot many things. So what all can be included in lust? Take a break off and think of all the incidences/things which make you crave for it, especially for your own gratification.
Is craving for Cigarette, Alcohol lust? Can anxiety of Tea/Coffee be considered as lust? Is wanting to talk with some one for long, day in - day out, be looked in as lust? Things will vary from person to person, but its important to be aware of them.
After understanding your short comings, its important to act on them. In this scenario, the simplest act that you need to perform is not to perform that act. This will need very high commitment from your side. In spite of you wanting to avoid the act, you will not be able to avoid it. Don't get dishearted. Try again. Some time down the line you will be able to have that commitment and the awareness to drop the cravings created within you. Experience it for yourself!