The best way to ensure your reception looks picture perfect is to assign someone, be it your favorite cousin, wedding planner, catering manager, etc., to double check and straighten every detail that makes up the place setting. While subtle, when these details are executed properly it makes the celebration that much more welcoming and aesthetically pleasing.
For chairs, the front of the seats should kiss the linen or if you are working with wood tables, they should line up perfectly when you look at the table from the side.
For charger plates and silverware, I personally like the the bottom of each to be lined up to the edge of the table, but whatever you personally prefer, make sure each place setting is consistent with the next. This level of organization offers a nice polish to the tablescape.
And then of course, making sure the dinner menus and any other decor such as a floral or ribbon is also consistently placed and double-checked. These details are there to ensure the guest feels special and thought of. That effort can be lost if the flower is just thrown on the table, barely making it on the napkin or even worse, forgotten all together.