Adam and I have been meaning to do this since we moved into this house a year ago, and we finally got around to it last week - we hung a mirror at Sam's height near the front door!
(Link to video)
I've found that Sammy is more willing to brush her hair or have it brushed as part of the "get out the door" routine. It's also a good way for me to remember it. She didn't have enough hair to brush until she was around 2, so I never really developed a routine that worked until we started doing this. She likes to brush and "style" her hair along with me, but that's not a daily occurrence. We tried brushing her hair when she got dressed, but the brush kept going missing and then I'd forget about it.
Now, we keep the brush in her "shoe basket." The shoe basket was one of our very first physical tools to help Sammy with her independence. I got the idea from Cornelia Lockitch in her parenting coaching sessions. Not only does Sam like to pick out her own shoes and put them on, but we've have never had any issue with her leaving her shoes and socks all over the place. She loves to put them in the proper place, and actually gets quite upset if we try to do it for her.
Keeping the brush there is probably not the most hygienic option, but I'll take convenience over hygiene any day.
As an aside, we've also had a Sammy-height coat rack since she was old enough to walk:
So as we got used to the hair brushing routine, Sam became more and more adamant about doing the brushing herself. She definitely needed a mirror, so we finally got it done, and she loves it! She does a pretty good job at brushing her own hair now. Many mornings I don't do anything at all, although her hair tangles extremely easily so sometimes she needs some help.
When it is time to get out the door, the only things that I need to do for Sammy are helping her get her socks on and getting the zipper on her coat started. I might not be so anxious for the end of winter if I use this time to help her master those last 2 skills. If summer comes and socks and coats go away, she probably won't try again until next year. But that's ok, too. In the meantime, we'll work on getting out the door in under 20 minutes. Now that's a challenge!