people are often displeased with some part of their life, but struggle to stop doing it. they call it a habit or addiction. it'd be better to recognize that problems are inevitable and solving them is not automatic.
don't just try to make yourself quit entirely. instead, pay more attention to what it's like when you do it. try to learn more about it. how does it feel? what do you like about it? what don't you like about it? try to be more introspective and understand the issue better.
when you understand it better, then you'll be in a better position to make changes, and to judge whether you have arguments/ideas/solutions/reforms/replacements/additions/etc covering the entire issue. you want a full solution that'll work in your life, rather than half of one. if you try to change with just half a solution, while mistakenly thinking it's a full solution, you're going to have a bad time.
let's use smoking and reddit as examples of things people want to quit. and let's suppose you want to spend more of your time reading books instead.
don't think about smoking or using reddit as all or nothing. stop assuming the conclusion (that you should have zero smoking or reddit in your life) before you actually change your mind. ;p
try to analyze what you like about smoking or reddit when you do them. go on reddit on purpose and focus on paying attention to your experience. smoke a cigarette and write down your thoughts. and don't be biased. say thoughts on any side of the issue, don't just try to be negative.
don't deprive yourself of reddit or use willpower to stop! don't self-coerce! try to use it consciously. if you catch yourself smoking, start paying more attention instead of just throwing the cigarette on the ground.
don't try to make yourself read books when you don't want to, either, just because you think reading is "good" and smoking is "bad".
don't be scared of your perceived flaws or weaknesses. don't beat yourself up. that gets in the way of problem solving. :(
don't hate yourself! don't think of yourself as broken or hopeless. problems are part of life. that's ok. the important thing is not to get stuck. learn about it, work on it, and you can change. stay optimistic. :)
relax. trying to quit your habit by tomorrow is overreaching.
having an activity in your life, and a criticism of it, is an unsolved problem. remember that you don't know what the right answer is.
don't try to force a preconception of the answer on yourself. start with an information gathering phase instead of trying to rush the solution implementation phase. have some patience.
when you actually change, it should be easy and feel natural. once you figure out the answer, in full, you'll be happy to do it. if you're having trouble changing, you don't know enough yet. there may be something good about your "habit" that you don't want to lose. there may be something bad about your alternative activities that you need to improve.