What do you do to get into a “character”?

I’ve been thinking of one of the new characters in the next book, getting into his mindset and wondered what other authors do.

So, that got me to thinking what lengths would you go to get into a character’s mindset in your Novels?  If your character was, say, a house painter who raises corgis, would you job shadow a house painter and volunteer to walk corgis from a shelter?  Would you paint for six months?  Or just interview painters?  Search a few websites on painting?