Brag about your skills, but not necessarily about your accomplishments. Tell a story about what skills you used to land a big account, not just that you’re now the number one sales person. People want to connect with you, not just watch you pat yourself on the back.
Let people know that you’re capable, not just a nice person. When someone offers a compliment on a job well done, thank them, and briefly let them know what you did to make that special thing happen. Make sure you take credit for all the great things you’ve done!