1) Regular Exercise (seriously, this is huge)
2) Get sufficient sleep
3) Cut out processed foods and minimize carbohydrate consumption (this is why both going vegan AND carnivore diets can work for this even though they seem to be in opposition)
4) Stay away from addictive drugs, particularly ones that impact neurotransmitters (e.g. Adderall/amphetamines)
5) Occasional use of drugs like Psychedelics or Ketamine
6) Get the fuck off social media and 4chan
If none of those things work, see a therapist or psychiatrist.
Depression can be alleviated, but it often requires lifestyle changes (exercise, sleep, patterns of eating and drug use) that many folks refuse to engage with.