Self-promotion has always been important, but maybe now more than ever.
I think Linkedin's just about the best channel for self-promotion, because everyone's there to do business already. So is attending events/conferences, for pretty much the same reason.
But some folks feel icky promoting themselves. Avoiding that is as easy as A, B, C:
1. Be authentic. Don't try to adopt a "sales" personality. The best sales person for you is you! Besides if you're super outgoing when you're promoting, but not in real life, people may end up hiring or referring you for the wrong reasons.
Be brief. Nobody likes long-winded self-promotion full of bragging and pomp. Figure out the most important thing you want people to know about you or your achievement (your main idea) and a couple of key details to expand on it, and then quit. (Here's a quick way to do that) That's all you need to share, at least at first.
Be casual. While you want to be able to promote yourself at a moment's notice, an over-rehearsed spiel is awkward for everyone and kills your authenticity. Memorize your main idea and key details, but "compose" on the fly so it feels fresh and friendly.