It's tough when you want your ability to be known, but you don't want to sound like you're full of it. By telling stories with examples of your expertise, you can express what you're capable of without sounding like a show off.
Photo by Erich Ferdinand
Nobody likes that person that just rattles off profound statements about themselves. They sound a little narcissistic and it's hard to tell if they're lying or not. Dorie Clark at the Harvard Business Review suggests a good story is your best bet instead:
...demonstrate your expertise with stories, not words. Saying "I'm great at pitching investors" sounds pretty egotistical. But sharing a compelling tale of how you rounded up seed funding allows others to deduce your skill without having to make it explicit.
Stories are also far more engaging and entertaining, as opposed to listing off a long list of skills and qualifications. Yes, you want to get across the point that you're capable and also kind of awesome, but you want them to really see why, not just take your word for it. If you're an expert at something, don't just tell them why, show them.
How to Promote Yourself Without Looking Like a Jerk [Harvard Business Review]