I think that every man in some point in his life feels unconfident.
What helps me is
1) dressing up nicely and even posing infront of the mirror ...dork

2) Listening to music that pumps up your energy (whatever your genres are)
3) Thinkin about situations that you felt high confidence and try to absorb that past feeling into the present. really helps
4) Tell yourself you're a good guy with good skills and you dont need to hold back.
takes some time to believe but inner game is a must
5) Learn some routines, even write them down so you'll feel like you always have something to offer to the conversation even if its some sort of game like the 5 lies game by Style
6) finally approaching, and whatever happens is for the best

just think of the good things that your approach can lead to and not the bad.