Given that Jonathan of Music Source has worked hundreds upon hundreds of wedding receptions, below are some tips that he has acquired that may serve you well.
If seating is 'not' assigned you will most likely have a few tables that are going to be reserved for immediate family, closest to the head table. Please make sure the guests that you want at the reserved tables know they are to sit at those reserved tables. It may also be a good idea to let your MC/Reception Director know who those guests are as well, or your greeters if you have them at your reception
If seating is assigned, do not seat older guests right near the DJ, but instead seat your younger adult guests at that table, as that is the loudest place in the room. If seating is assigned, it is recommended that you have greeters at the door to direct guests to their tables.
Bustling the Dress
It seems like 50% of the time the bride has a hard time getting her dress bustled prior to the formal introduction. There'll be two bridesmaids and mom working on it for 10-15 minutes before they get it correct. Brides, please practice this as it is cutting into your own reception time and causing your guests to wait even longer.
The formal introduction is basically the start of all the formalities at most wedding receptions. Please tell everybody who is going to be introduced when it is to happen so they are not missing in action when the time comes. Whether you select one song for everybody or one song for each couple, make sure that it's appropriate and can be spoken over without too much trouble. So for example, rap songs typically make horrible introduction songs as they are too wordy, there's too much focus on the beat, and they tend to lack the musical instrumentation and necessary rhythm.
To see the 50 most popular wedding party introduction songs in 2015, go to pages 15-16 here > http://www.djintelligence.com/charts/DJIntelligenceMostRequestedWedding2015.pdf