Here are few points which one should remember to maintain his mental health.

Value yourself -

Treat yourself with kindness and respect, and avoid self-criticism. One who respects himself, world respects him.

Take care of your body -

Taking care of yourself physically can improve your mental health.

Surround yourself with good people.

Reward yourself on your little achievements.

Learn how to deal with stress.

Start learning how to empty your mind.

Set a goal which you can achieve. (Sometimes, we set something which is unimaginable or unreasonable.)

Keep away yourself from who are careless towards their mental health.