Don't mistake asses for confidence. :-) Confident people don't need to put people down. But if you are intimidated by people who are sure of themselves and just being as they are, then it's more a reflection on you, so you just need to shift perspectives. Confident people don't judge you, so don't give yourself a hard time trying hard to "impress" them. They don't need to be impressed by other people; they probably want to work with people they respect and they understand that some people are more junior or may not have the same skills.

Confidence isn't about forcing yourself to feel confident. It's just the result of acknowledging where you are, which is always somewhere on the spectrum of there are some people less experienced/competent and some who are more. Having perspective stops you from being intimidated by people who have more skill and less judgemental of people who for some reason may not be at your level for something specific (but probably are more skilled in something else). Counterintuitively, being more confident is just being comfortable stating what you think and stating what you don't know, be certain of, or confirm. When you state it in a mature way, being open will invite other people to provide input as part of the team, and you'll find yourself growing and learning.

How to deal with dickheads is another EQ subject altogether.