様(よう)にするTo try to, To make sure to, To endeavor to

The difference between the two lies in the level of effort or intent. When we say ようにする, we express a strong intention or effort to do something, like a resolution or a promise. It's like saying "I'll make sure to do this". In contrast, 〜ようとしない indicates a lack of effort or willingness; it's as if you're avoiding to do something or simply do not intend to, such as "I won't try to do this".

The phrase "ことにする" is used to express a personal resolution or decision that has already been made, hence it comes across as more conclusive or final. For instance, you may use it to say "I have decided to quit smoking". On the other hand, "ようにする" signifies an ongoing effort or intention to do or keep doing something; it suggests a more proactive and continuous endeavor. For example, you might use it to say "I try to do exercise every day".

The phrase ように～てほしい essentially expresses a desire or hope for someone else to do something or for something to happen in a certain way. On the other hand, ようにする is more self-directed and describes someone's personal effort, intention or habit to make sure something is done or happens in a certain way. The former is used when your wish or desire involves someone else's actions, while the latter is more about your personal actions or habits.

While both "ようにする" and "てみる" relate to the idea of "trying," they convey slightly different nuances in Japanese. "ようにする" implies a continuous, habitual purpose or effort, like making sure to do something as ideally or regularly as you can. On the other hand, "てみる" carries the sense of testing or experimenting, and is used when you are going to try something out to see what happens, emphasizing a single instance of trying rather than a sustained effort.

The phrase "ようにする" suggests a habit, routine, or an ongoing effort where the doer is actively trying to complete an action, while "とする" after a volitional verb implies a one-off endeavor or attempt or an action one is about to take. For example, "毎日運動するようにしています" would mean "I make it a habit to exercise every day", whereas "運動しようと思います" would mean "I'm thinking about exercising" or "I'm about to exercise". Thus, "ようにする" demonstrates a more self-disciplined, habitual action, while "とする" is indicative of one-time attempts or future plans.

The grammar point ようになる is used to express a change that has taken place over time or will take place in the future, to signify that something reached a certain stage or state. On the other hand, ようにする is used when someone is making a conscious effort or intending to do something. So, the main difference lies in whether the action or state is a natural change (ようになる) or a result of one's deliberate effort (ようにする).

The Japanese phrase ように is generally used to express a purpose or a certain method, and can be translated as "in order to," "so that," or "in such a way that." On the other hand, ようにする adds a sense of personal commitment or effort towards a goal, and is better translated as "to try to," "to undertake to," or "to make sure to." While both express a goal-oriented statement, ようにする emphasizes the speaker's effort or responsibility to achieve that goal.