One common way to reduce stress is to simply sit, breath gently but deeply, and not think, for five minutes. This sounds simple but can take some practice. Some find it helpful to focus on their breath to help keep the mind from wandering back to the day's stressful issues. There are many techniques available. Some visualize a peaceful place out in nature and imagine themselves soaking up the serenity nature affords.
Some people use relaxations tapes and soothing music.
Others work out, go for a brisk walk, or practice yoga. It's helpful to set aside times for recreation, hobbies, and play. Some people find that music, poetry, or artwork, are creative outlets that they find both relaxing and healing. Maintaining a healthy and balanced diet allows the body and brain to heal. Our bodies need a regular source of good quality fuel to work efficiently.