Don't hesitate to give your wedding party a timeline. Even if you don't work with a Wedding Planner, you should create a timeline for the day and give that to the people involved. Email everyone about a week before your wedding, not too soon or they will forget about it and not too late or else they won't have had time to review the details. This way your wedding party will know what you expect for your wedding day and where they are expected to be. This will definitely alleviate some stress on your part and will make the day easier for everyone!