What it means
ようにする expresses a deliberate effort, habit, or decision to make a situation happen in a certain way. It is commonly used after a verb in the dictionary form to say that someone will try to do something regularly or will make sure to do it. After a verb in the negative form, it means making an effort not to do something. The subject is often omitted when it is clear from context.
Usage note
Do not confuse ようにする with ようになる. ようにする focuses on a person's deliberate effort or decision, while ようになる describes a change or result that comes about.
How to use it
毎朝、野菜を食べるようにします。
I will make an effort to eat vegetables every morning.
夜は遅くまで起きないようにします。
I will make an effort not to stay up until late at night.
毎朝、野菜を食べるようにする。
I will make an effort to eat vegetables every morning.
夜は遅くまで起きないようにする。
I will make an effort not to stay up until late at night.