As you begin to think about who is going to sit with whom (which is always a daunting task) keep in mind how many people you are placing at each table; also keep in mind that the waiters need room to serve between tables and that should be a consideration if selecting round or long tables pending on the venue size and shape.
When considering how the place settings will fit on the table, you must think about glassware. Will the champagne glasses be set at the top of the meal or bought out only for the toast?
You can not neglect to think about your centerpieces if they are high make sure they are high enough not to block the view of your guest sitting across from each other. If they are low you may want to add different heights of candles so the room doesn’t feel one-dimensional.
Use the attached photo as a guideline if you are having a formal wedding to imagine your centerpieces, candles and what your actual table will look like. The last thing you want is an over crowed table. Sometimes less is more.