Your wedding rehearsal is a time to make sure all of your ducks are in a row and ensure any last-minute details are confirmed. You'll of course run through the ceremony and ensure that everyone's roles are clear. What shouldn't happen, though, is anything that will confuse your wedding party or create more stress. Here, everything you shouldn't do at your wedding rehearsal.
First, trust your officiant to lead the rehearsal. Remember: They've done this before! They will know what they're doing and will instruct you and your wedding party on how to proceed. This also isn't the time to make major changes or introduce any ideas. Your rehearsal is the moment in your wedding planning to solidify all of the arrangements, not brainstorm new ones. If you do try to make changes it will just confuse everyone involved and potentially create a mess of your ceremony. One change you will want to introduce and go over, though, are any variations to the ceremony you're planning to incorporate such as readings. Make sure the officiant and whoever is participating in that deviation are prepared for the big day!
Don't forget to rehearse any special roles, too. Anyone who's doing so much as lighting a candle should be present and and enact their part to make sure they're prepared. Also don't forget to have a clergymember or wedding planner explain to ushers the protocol for seating guests at the ceremony so that set-up and seating goes smoothly. Last but not least, don't forget to bring fake bouquets so the walk down the aisle is as real the night before as it is on the big day.