The knowledge of yourself will preserve you from vanity.

Vanity depends on a flattering blur. Anyone who has looked closely at their own record, the parts they got lucky with, the parts other people carried, the times they were plainly wrong, finds the inflated version hard to maintain. Self-knowledge is not self-criticism. It is accuracy, and accuracy deflates the puffed-up parts by itself.

Try writing an honest account of something you are proud of, including who helped and what went your way. The pride usually survives and becomes steadier for being true. What falls away is the need for anyone else to confirm it.