Don't panic! Everything will work out fine. I would always suggest booking your photographer first and seeing what contacts they have, more often than not we have a phone book filled with trusted professionals.
Subtle additions can make a day that much more personal. We provided a Slideshow of the couple and their families life up to the wedding, it showed their journey so far and captured how much further they have to go.
There can never be a 'Number 1 photo'. Every wedding is unique and it all comes down to the style of the wedding and what the couple is willing to do.
Rain should never be an issue, we have plenty of brollies and we'll avoid the grass!