There should be at least two more if your gown is custom-designed or if you plan to lose weight. Wear the right lingerie. Lift your arms. Make sure you can hug people and dance. Check the length.
Many brides end up stepping on their hems.
Try your shoes on with your dress and spend some time walking around during the fittings. Don't worry about that one flower at the shoulder or waist that doesn't seem quite right. Details can be worked out later. The most important element to decide first is the silhouette of the dress and the way it makes you feel. Don't get frazzled.