One thing that I've learned over the years is to have your modelling lamp on for your strobe so you can see exactly where you want the light to flash. I wanted just a small amount of light to come over her shoulder and accent her neck while letting the groom's suit fall to shadow.
I told the bride and the groom not to worry if it rains... "we can get creative." Which in mind I was thinking... "I better get an awesome shot because they are already upset about the weather."