Interesting thread, and the responses really resonate with me. Traci you look really great in that outfit.
I'm thinking that what mostly helps me move behind that mindset when I feel the same way is 'fake it until you make it'. The only way out was through, just to wear the clothes, and see how you feel at the end of the day -- was it a positive experience overall or was there something that needed adjusting, and the next day try a different outfit that is also a tiny bit of a stretch until your comfort level gradually finds balance.
Like viva says, most people aren't going to even be paying attention to you, and the few who do, might compliment you. If I saw viva rush by in her coat in the airport, my thought would be omg I need a bright winter coat how fab.
Also I tell myself, who cares what the 'who does she think she is' voices think (whether internal or external). All they want to do is make someone feel small and powerless, they are better off disregarded.
ETA: cross-posted with viva, but yeah that makes sense, that: wearing something outside my own norm and feeling differently about myself is the real barrier. Then it becomes, given a little adjustment time, is this 'different' inauthentic in some fundamental way, or is it something that could feel good or expansive or uplifting?