[influx]

Conversely, tend towards saying yes if someone you want to hang out with invites you out, as they usually ask once and never again.

[globular-toast]

This. You usually get one and only one chance with new people. People hate rejection and they're not going to keep asking.

So a pro tip: if you're starting a new job or something and want to integrate into the social circles, be prepared to drop everything for those first few invitations. The first one is basically mandatory.