I have many people who come to counselling looking for suggestions on staying calm and having a better, peaceful life. I work with individuals by explaining that life is entirely of choices, and it's up to them to decide how best to live their lives and what challenges they want to take on. Sometimes, this requires taking on a challenge to obtain peace later on (for example, going to school). Other times, it means evaluating what is happening in your life and assessing the situations influencing you to feel the way you do. This may mean choosing to take on less when you can and adjusting your life when challenges present themselves (i.e., a sick parent).
Part of keeping calm is working on creating practices that support self-care. This may mean engaging in a meditation practice that supports taking time to breathe and train so that when you need to feel regulated, you have the skills necessary to do so. Several resources are available to help you with your meditation practice online and at the local library. What I like about meditation is that it gives you a bigger bandwidth to deal with life stress, which in turn brings on more feelings of calm and ease. What is most important to consider is how often you practice the meditation. The recommendation is to do it daily for at least 15 mins.
Lastly, assessing your thinking could also be imperative to living a calmer life. This may mean lowering your standards and adjusting your expectations of people. It may require time and constant introspection, but it could serve as a valuable suggestion if done correctly.