You've already taken the first step. You realize you say it all too often. Be aware of saying it - and concentrate on NOT saying it. Skip a beat and say it silently (in your head) if you have to use the word. Eventually, you'll be able to stop saying, "like" as if it never was a crutch for you.
Know that there are different words or catchphrases that are used by "the masses". Cool, far-out, groovy, whatever, as if, dude, sweet, gnarly, rad...all examples that people over-used then overcame.
You can do it!