What's the most effective way to prevent feeling stressed?

See Below: Establish small, achievable goals. Try to identify things that you can control and things you cannot control. Work on things that you can control, and let go of things that you can't. Establish routines for yourself-- it helps make environment more predictable. Do relaxation, self-care, sleep hygiene. Find a therapist to help you guide through the process.

Balance in your life: Balance in your life is important. Especially work/life balance. Also eating right, exercise, proper sleep and good coping skills such as deep breathing will all help reduce stress. Remember, you are in control of your body!