Jumping in the deep end

In the past month two work colleagues have announced they're getting hitched next year.
As soon as I heard the happy news I instantly volunteered my services as a photographer, an offer that was taken up with enthusiasm.
Now, both ladies are easy going and laid back and both are having small, relaxed weddings.
And one I'd call a friend; the other a close acquaintance.
So I want to take the best photos possible. I'm very excited about this, but also a *tiny* bit nervous...