Decide firmly that you will not gamble and then block the gambling sites. Try spending more time with family and friends. Use less internet and try to keep yourself busy with other thing like some new hobby or keeping yourself busy with work. Leaving anything's addiction is possible if you firmly decide to do so.
Nope, it all depends on the reason on why you gamble...If you are not attached to gambling, say, you are not interested and just trying it, then definitely shifting your focus to new things could work, but if you are addicted to gambling because that is your source of bread and butter, then definitely it is hard and I think only new ways of earning is the only way that could turn you away from gambling..