Perfectly neat, polished updo's are OUT (although if it was done well I don't think it would garner much criticism). What I read says that slightly "undone" updos are IN. If that's the case, I have 3 steps to a quick, attractive, but not perfect updo.
Step 1 - Gather your hair in the back as if you're going to put it in a ponytail.
Step 2 - Start twisting the hair you're holding upward, like it's going straight up the back of your head
Step 3 - Hold it in place with one hand, and with the other clip the ends to the top of your head with a decorative clip. You can tuck the ends under the clip or leave them out for a more messy, undone look.
That's it - your hair should look like this from the back:
I usually pull the front down so I have some long bangs hanging in my face. I think it looks sexier that way, but that's a personal preference.