Habits
Via associations
For example, even if the negative health effects of drinking may not bother you too much, you can still associate it with the things which are more personally powerful to you. For instance that it makes you fat and smelly. Each person has different things which cut deeper or shallower, even when those things aren’t terribly valid. Even a fault can be used to your own advantage.
It can also go the other way with positive association, though I think this is much more difficult to apply as it requires the willpower to not do the positive thing in absence of the habit. If you had the willpower for that, you’d probably have the willpower for the habit.
Via replacement/enhancement
You can replace up your existing habits to better versions of them, and you can do that iteratively. Say you have a very simple habit of listening to podcasts. Start walking while listening, then start running some of the time, then all the time, etc. THough small iterations you can go from a very simple easy habit to a much harder one. The reverse of this happens naturally, where you have a good habit and slowly let it degrade.
Starting
Starting a habit is the most difficult part of any good habit. It’s not the majority of the work, but it is the most difficult singular moment. You must start something form nothing. It is then important to start as small as possible. As yourself: what is the simplest possible thing I could do which would still qualify as “the thing”? I cannot stress this point enough - it is important to start small, microscopic.
When you start a habit, you are not starting the thing, you are just creating the environment in which the thing can grow and live on it’s own. If you do not have this baseline, then even if you get some progress into the habit it will eventually die.
I remember reading of someone who started going to the gym. They started by just putting their shoes on. Then they put their shoes on and drove to the gym, then drove right back. Then they did that and did 1 set. Each of these steps could take weeks or months. But that doesn’t matter, if it ends in you creating the context with which the habit can thrive, then it is worth the investment.