I once read a quote, can't remember who off the top of my head, that said the process of writing was to follow the character around and see what interesting things they do.
I've used this as a writing exercise many times. Start with the moment I see them clearly, either middle of the day, as they're getting out of bed, etc...and just follow them. Yeah there tends to be boring stuff like breakfast and watching the news, but I find that if the character is interesting (as I know they must be, otherwise why would I be following them?) then usually Something Happens, and it catches me by surprise as much as the character. Such as that bit there about eating breakfast and watching the news, well perhaps there's a news story that comes about again later and brings up things for the character to deal with. Sometimes their entire day is just a bunch of comical gone-wrongs that at the time must be frustrating, but in retrospect are amusing.
As for re-writing for a different genre, I do that all the time. by the time I'm done though, while the basis might have started off the same, I find I end up with two different and unique characters.