I planned a "medium" amount. Some of it was unplanned (well, originally he was going to move to the US!), but we took a year to get married and get the visa sorted and during that year I researched the visa, looked at what I would need for the "next" visa, started throwing together a Cv and etc. I didn't really have a lot of free time though as I was basically working two jobs to get ready to move.
So, I would say that I focused mostly on the visa/legalities/driving license stuff and that's it. We were lucky enough that I didn't have to find a job right away, so I knew I would have a few months to find cocoa powder in the supermarkets and etc. I had also been living with him in his flat every summer for five years...so it was more like moving to my "other" home than leaving home completely.
Oh, I feel I should add that BY FAR I spend the most time trying to find somewhere to horseback ride over here--and locating the nearest library. With my two hobbies taken care of, and the prospect of living permanently with DH, I was pretty much set!