About 20 years ago, I read something Don Juan said to Castaneda: we can quit smoking very easily, just by snapping our fingers. You don't have to make your enemy too powerful; you just have to deal with him easily. And I quit smoking then, very easily. Sometimes, once a year, I smoke a cigar, but it's just a treat; I can easily do without it.
When it comes to alcohol, when I want a drink, I buy a minimal amount, like 100 ml of cognac. I drink it, don't get too drunk, and don't want another shot.
I have no addiction to chips and sweets, I used to play computer games at night, but that was when I was 20 and it went away on its own.
What I don't want to give up is my habit of reading. I'm currently reading Count Ségur's notes on 18th-century Russia. It's a great pleasure to immerse myself in the lives of people of that era.