I am have OCD when it comes to my scale
I weigh myself every morning after I pee in my birthday suit. I take any
jewelry off and I comb my hair getting broken hairs out. Now, I know I know, loose hairs aren't going to affect my weight, but like I said, OCD! Oh, and with the after shower thing - my hair comes down to my mid- to lower-back, and I have a lot of it, so, with that said, I have never weighed myself post-shower.
The key is (or so I have been told) is to just be consistent. If you weigh yourself naked, always do; if you weigh with clothes on, always do; weigh yourself at the same time(s) of day, etc. etc. I like to weigh myself every morning cause, like others have said, it makes me think, "you're going to have to weigh in tomorrow, do you really want to eat all those salty chips?"