How exciting!!!
Tell the photographer (and videographer, if applicable) if there are any specific pictures or poses the couple wants. While you're at it, tell the photographer if there are any shots the couple DOESN'T want. I wish I had another dozen pictures of us with our toddler niece, with DH's grandmother, with my father, or with my best friend/maid of honor instead of the pile of 'stylish' prints we specified we didn't want in the first place!
Also, if the bride and groom will be serenaded make sure the photographer and videographer captures those moments on film. Thank heavens our photographer got that right