This book helped me a lot:
The Depression Cure, Dr. Stephen Ilardi outlines a "Therapeutic Lifestyle Change" (TLC) program based on six lifestyle elements designed to align modern life with our ancestral biology.
The six steps are:
Dietary Omega-3 Fatty Acids ("Brain Food"): Increasing intake of omega-3s, particularly EPA and DHA found in fish oil, which are essential for proper brain function and reducing inflammation.
Engaging Activity ("Don't Think, Do"): Participating in meaningful, absorbing tasks to fight rumination (dwelling on negative thoughts), which is a primary driver of depressive episodes.
Physical Exercise ("Antidepressant Exercise"): Regular aerobic activity that stimulates the release of neurotransmitters like dopamine and serotonin.
Sunlight Exposure ("Let There Be Light"): Using light—ideally natural sunlight or a high-intensity lightbox—to regulate the body's internal clock and boost mood-lifting chemicals.
Social Connection ("Get Connected"): Prioritizing frequent, face-to-face interaction with friends and family to prevent the social isolation that fuels depression.
Healthy Sleep Habits: Establishing a consistent sleep routine to allow the brain and body to recover, as chronic sleep deprivation is strongly linked to depressive symptoms.