It means:
Look after yourself physically - clean teeth, regular showers, nice clean clothes, healthy food, no abuse of drugs, tobacco, alcohol, regular good night's sleep and plenty of fresh air and exercise.
Look after your environment so you live in a welcoming space - clean, tidy, comfortable bed, clean bedlinen and towels etc
Look after yourself mentally - use CBT techniques to reduce aggressive self-chatter, meditation to reduce anxiety, learn to say no so you are not overloaded with responsibilities
Look after yourself emotionally - avoid people who use you, mock you, talk at you, show no interest in you but expect you to show undivided interest in them. Cultivate relationships with reliable, kind people who are fun and energising to spend time wiht, who share core values with you.
Treat yourself occasionally - allow yourself to spend money and time on things that matter to you and give you great pleasure. Don't always put others - children, partner's, parents', friends' material (or emotional or physical) needs before your own.
You could add look after yourself spiritually and intellectually too.