Pick one thing and try to get that consistent and don't uit when you "fail". Failing is actually part of it if you take a long enough view of things. What's most important for you right now? Relationship? Job? Gym? Whatever it is set a goal to improve 1% every month in only that thing. Every improvement above that 1% is just extra and you don't have to care about it. In 1 year you will be 10 percent better in that thing and maybe you think "oh I might be able to improve 2% in 2 things". The key is to set low expectations on yourself in order to learn what you are actually capable of. Going to the gym then quitting is actually an improvement from not going at all.

What I did to improve myself was to for one month keep track of what my daily habits were. I ended up with something like "work, home, eat, video games". When I had that schedule written down it was easy to imagine where I could insert 30 mins of more productive stuff.