Confidence is what everyone across the board says is the most important thing. Arrogance is often misconstrued as confidence. It's absolutely true.
Sure, but there’s no hack to gaining confidence. It can’t be practiced and faked. That’s not confidence, that’s show and comes off as not being genuine confidence which can come off similar to arrogance.
I don’t know how to help with the magical confidence equation. I imagine it’s different for everyone. I’m really introspective and quiet in my mind, but people think I’m outgoing. I say “what? No, I’m shy, I always have been”. I always was shy. Apparently I’m not anymore. But innately that’s still my personality and how I view myself. I still am introspective and I’m certainly not loud and boisterous but apparently I’ve become very social and conversational and comfortable. Confident I guess. For me I guess three deployments in an armed career field, getting shot at, returning fire, arresting people, dealing with suspects and victims and witnesses regularly, being in a high pressure SWAT role, being in really good shape, having to do a lot of public speaking... if I had to guess those were the ingredients that turned into confidence for me.
Obviously not everyone can do all that and not everyone would want to, nor would it work for them. But if I were to suggest anything that I think would help, I would say, for certain get in the best shape you’ve ever been in. That always assists with confidence. No way around it. Find a good barber and get a sharp haircut. Something you wouldn’t usually do. Ask their opinion. Simplify your wardrobe. No idea how you dress, but a few pairs of well fitting jeans and plain, neutral color t-shirts without logos or words on them is classic. Add a couple nice knit sweaters. Easy. I don’t think I own a shirt that I wear outside of the gym that has words on it. Get a nice pair of boots too. Thursday boots are great and fit any wardrobe. With fitness and fashion out of the way, join something like toastmasters or an online debate club. Practice public speaking. A lot. And also maybe find something like a boot camp/survival skill weekend getaway. Instead of spending money on dating services spend it there. You can’t just synthesize confidence but those are the types of things that will help develop it. Make sure you know how to do simple things like sew a button, change a tire, start a charcoal grill. Simple, simple things. Know how to order a good cocktail and how to recommend one.