Well for one the last pic you posted is pretty much a disaster. It looks like you have a shirton with epaukets and still decided to wear a tie with it. I'm guessing since you are doing the photography for the wedding you decided to dress comfortably (I hope you were) if not then putting the fit into perspective makes it worse regarding the fact you went to a wedding with a utility shirt, knit tie and no jacket
Also you tie clip is too high for my tastes.
The other pic. Not sure where I start
Under normal circumstances I would never recommend the good taste thread since I disagree with what it stands for, but it wouldn't hurt for you to check it out to understand color cordinations and combinations. Throwing shit together isn't for novices. like i noted earlier, for now leave that Barims and Labelking
The pic with the bride and groom I was posting to show that I'm a wedding photographer and use the strap for what is actually intended for, the fit is irrelevant as I wasn't trying to show ya the fit, believe me I know it's a mess, you try shooting a 14 hour wedding and see how you end up looking
As far as your other suggestions, thanks I know there is always room for improvement, well noted