If you can look at yourself in the mirror, and smile at yourself, then the attitude of others won't affect you. It's not about the outlandish and egocentric 'love for yourself; it's all about accepting yourself 'warts and all'.
If you can be the first one to make fun of yourself, or laugh about your failing first; then it prevents the actions of others bothering you. If you can ' not give a shit' what others think of you when you are being yourself; then its their problem, not yours, if they feel uncomfortable with your reactions, or actions. They are at fault, not you. The onus is on them to change their attitude towards themselves; because they clearly don't have the same attitude towards themselves.
Those who portray extravagant outward behaviour, and demand to be the centre of attention, are usually extremely insecure individuals ... generally, there is a clear difference between their 'egocentric' behaviour and someone who has a true love of self and is comfortable wearing their own shoes. They just are; they care little about what others say to them, or say about them. Those with the insecurity are usually the first to 'run to teacher' or the boss, to complain about you.
Self love is everything. You have accepted who you are; where you are in life. You can accept you are not perfect ... but you like who you are. By laughing at yourself, when faced with adversity or an overbearing rival/peer; by willingly wearing the 'Joker's Hat'; you will diffuse what could have been a bad situation. You are subliminally telling the rival/peer that 'your belittlement won't harm me as you are not attacking any weakness' ...