There are four rules that are needed to successfully form a new habit, and the opposites of these rules will break or prevent an existing habit.

Disclaimer! All the information is taken from Atomic Habits by James Clear so if you find this interesting you should check the book!

01: Make it obvious

The main idea is to make your habits stand out, make them specific. Once you decide a time and a place to do them, you don't have to wait for inspiration to kick in. There is no need to make a decision. Simply follow your predetermined plan.

The simple way to apply this strategy to your habits is to fill out this sentence:
I will [BEHAVIOR] at [TIME] in [LOCATION].

Another good trick to make them unavoidable it's called habit stacking. Rather than pairing your new habit with a particular time and location, you pair it with a current habit.

The habit stacking formula is:
After [CURRENT HABIT], I will [NEW HABIT].

The key is to tie your desired behavior into something you already do each day. Once you have mastered this basic structure, you can begin to create larger stacks by chaining small habits together.

Environmental cues:

The cues that trigger a habit can start out very specific, but over time your habits become associated not with a single trigger but with the entire context surrounding the behavior. A stable environment where everything has a place and a purpose is an environment where habits can easily form.

If you predispose your surroundings with the stuff that makes you remember your habit, you will probably be inclined toward that habit, even subconsciously. When you are at a party drinking with friends you probably drink more that if you are alone, that's because your context at that time makes it attractive to drink more. And that take us to our next rule.

02: Make it attractive

Habits are a dopamine-driven feedback loop. Every behavior that is highly habit-forming—taking drugs, eating junk food, playing video games, browsing social media—is associated with higher levels of dopamine.

But dopamine isn't released only when you experience pleasure, but also when you anticipate it. And when dopamine rises, so does your motivation to act. It is the anticipation of a reward—not the fulfillment of it—that gets us to take action.

Culture:

We are drawn to behaviors that earn us respect, approval, admiration, and status. The culture we live in determines which behaviors are attractive to us. We tend to adopt habits that are praised and approved of by our culture because we have a strong desire to fit in and belong to the tribe.
One of the most effective things you can do to build better habits is to join a culture where your desired behavior is the normal behavior and you already have something in common with the group. So for example, if you want to start jogging more often, you could start by jogging with other people and making runner friends.

03: Make it easy

To make a habit easy is to stop pressuring yourself to archive big goals in short periods of time. You don't need to start from zero to two hours at the gym every day. Just being there every day (or three times a week, whatever) it's enough to start, even if it's just 10 minutes.

Habits are the automation of repeated tasks, so when forming a habit it's better to make a lot of simple repetitions than a few hard ones. Then, when you have form the habit, you can focus on improvement.

Human behavior follows the Law of Least Effort. We will naturally gravitate toward the option that requires the least amount of work. Create an environment where doing the right thing is as easy as possible and doing the wrong thing is as hard as possible. If you want to stop using your phone each morning when you wake up, why not put the phone away or in another room?

Decisive moments

Every day, there are a handful of moments that deliver an outsized impact. The moment you decide between ordering takeout or cooking dinner. The moment you choose between driving your car or riding your bike. The moment you decide between starting your homework or grabbing the video game controller. These choices are a fork in the road.

We are limited by where our habits lead us. This is why mastering the decisive moments throughout your day is so important. Each day is made up of many moments, but it is really a few habitual choices that determine the path you take. These little choices stack up, each one setting the trajectory for how you spend the next chunk of time.

Procrastination

The idea is to make your habits as easy as possible to start. Anyone can meditate for one minute, read one page, or put one item of clothing away. And, as we have just discussed, this is a powerful strategy because once you’ve started doing the right thing, it is much easier to continue doing it. A new habit should not feel like a challenge.

The secret is to always stay below the point where it feels like work.

If you show up at the gym five days in a row—even if it’s just for two minutes—you are casting votes for your new identity. You’re not worried about getting in shape. You’re focused on becoming the type of person who doesn’t miss workouts. You’re taking the smallest action that confirms the type of person you want to be.

04: Make it statisfying

We are more likely to repeat a behavior when the experience is satisfying because the human brain evolved to prioritize immediate rewards over delayed rewards. The Cardinal Rule of Behavior Change says that what is immediately rewarded is repeated and what is immediately punished is avoided.

One of the most satisfying feelings is the feeling of making progress, for this reason one way to feel like progress is by using some kind of habit tracker. A habit tracker is a simple way to measure whether you did a habit—like marking an X on a calendar. Habit trackers and other visual forms of measurement can make your habits satisfying by providing clear evidence of your progress.