You know, it's very strange. I didn't use to be a fan of tie bars. I actually thought they gave off a bit of a pretentious look that I wasn't fond of. Well thank God, because the times have changed and I'm now very much on-board the tie bar train. I want to slap my old self for thinking the way I did.
Anyway, yes, definitely make sure your tie bar is shorter than the width of your tie, as otherwise, it can look ridiculous. I recommend having the tie bar hit at least the middle of the tie, but don't feel the need for it to extend all the way out and match your tie's full width. 1 and 1/2 inches is a good length I'd say. Also FYI, I only shop at one place for tie bars: it's The Tie Bar.
Sigh, I love watches so much. This particular accessory has a special place in my heart, and I promise to you that I'll be writing about them soon enough.
The interesting thing about this rule for me, is that I agree with it wholeheartedly, but think that you can make one exception. I'll get into that exception in just a second, but yes, you shouldn't be wearing digital watches to any formal event (or any event that isn't extremely casual, in my opinion). As a general rule, larger/thicker watches are for more casual events, and slimmer, smaller watches are for more formal events. The ideal dress watch is slim, simple, analog, on a black or brown leather band, and under 38/40mm in diameter. Casio G-Shocks should be left for going hunting or hiking, and blingy/oversized fashion watches should be left for... never.
So the exception I'm talking about is regarding the ability to use a nice diver watch (metal band, a bit thicker and bigger than a normal dress watch) in dressier situations. Big watch snobs will tell you that you should never do it, but I disagree. I think a nice diver watch, as long as it's not too thick or loud-colored, can look amazing underneath the cuff of a nice suit. Just my humble opinion.
So this rule is pretty self explanatory. Just like the rule about watches, this one is about wearing your accessories appropriately. Don't pair a business casual outfit with Nike Wrap Sunglasses. Save that for when you're wearing a track or wet suit. Trendy hipster glasses probably aren't the best fit with a semi-formal/formal outfit either. Use common sense on this one, and remember, the less flashy the eye/sunglasses, the more appropriate they probably are in most situations.
Leave loud colors and patterns for casual-wear, and stick with tortoise, black, or metal-colored frames for formal-wear. I recommend just buying a pair of Ray Ban Aviators or Wayfarers and calling it a day. Those classics work in basically all situations.
So there you have it- some rules to keep when wearing accessories. Basically the main takeaway is that you should consider how your accessories will work with the rest of your outfit. Matching/pairing appropriately will make a huge difference, and it's important to remember that.
Really quickly, I'm also going to say that I believe less is more in the case of men's accessories. It's definitely cool to "up the game" of your outfit with some nice accessories, but sometimes, I say it's okay to put down the pocket square, eyeglasses, diamond studs, and bracelets. Just put on a wristwatch and call it a day.