In Christian ceremonies, the bride stands on the left side of the alter. In Jewish ceremonies, the bride stands on the right. Traditionally, family and friends sit on the side of their relation. BUT...
One of our favorite rules to break is for family members to SWITCH sides in the front row so they can see their son or daughter's face during the ceremony. Otherwise, your parents will be looking at the back of your head while you stare into your partner's eyes.
Lots of couples these days ask guests to "pick a seat, not a side" during the ceremony.
Anyone walking in the processional, like parents and grandparents, should have reserved seats in the front row. Additional family, like siblings and close aunts and uncles, should have seats in the second row.
We also like to encourage saving a few seats in the back easily accessible to any late arriving guests.