Catch yourself feeling insecure.  Ask yourself why.  Tell yourself a different story.  Start to feel better.

Example: I’m in a room full of people, some of whom I kinda know, some of whom I don’t know at all.  Sometimes conversations dissolve or whatever, and I’m standing around sort of awkwardly.  I feel bad.  Why?  Because at some level I’m imagining someone watching and mocking me.  I’m saying “well I’m inherently awkward, of course nobody wants to talk to me.”  This is a story.  It is not objective truth.  We all tell ourselves stories, and it’s hard to turn it off.  But as long as I’m constantly telling myself a story, why not at least make it a good one?

I think for many social cases I’ll replace this voice with a younger cousin, like 4 years younger.  Younger cousins always think older cousins are the coolest dudes on the block.  (at least I do.)  Say I’m standing around awkwardly; younger cousin doesn’t even see that.  He just sees older cousin Dan hobnobbing with awesome folks, because of course he is also an awesome folk.

So look out for this.  There’s more than one way to view most situations.  You’re probably unconsciously picking the pessimistic one.