Have a tick list for the day, so you do not forget a single thing. Far easier to edit down your master tapes than to lengthen them. Focus on keeping the camera still ( unless you are adept at tracking ).
A little bit of the location, but go back and shoot more folk. Engagement could be a busy and overpowering time for all parties involved. Make a practical evaluation of how much you can spend. A good accountant may help out in this area. You cannot do two things well, so focus on getting the footage. Edit cold heartedly, you hear me? Keep the first gurus for sure, but if possible get the satisfied couple to see your edited masterwork before they see the long version.