The trick there is to become invaluable; to be a specialist in a certain area (like security, database management, native mobile development, data science, AI, etc) and make yourself in demand. If you keep talking yourself down by saying "Yeah I know such-and-such but it doesn't matter because muh personality", then you will keep having no chance at promotion.

Actually in the IT world, it's better to switch jobs than wait (or ask) for promotion.

TL;DR: Be confident, know what you know, know what an employer needs, sell that.