I shave with mach 3 turbo in the shower. No mirror needed. Only have cut myself once.
Are you planning on shaving it, or using clippers and cutting it without a guard?
I would never Nair my head, that sounds terrible. Just throw some shaving cream and shave with the direction the hair grows. You could go against the grain, but I don't recommend it. I've done it, and unless you have a brand new razor then it will be hell. Like I said, you get so used to it that you can do it in 10 minutes and not even need a mirror. I shave it about every 4 days. I usually shave with a new razor, then use that razor for my face for the week. Then use it again to shave my head. Then it starts getting a little worn out so I'll replace it.
I can't imagine the shock of going from hair one day to bald the next. I gradually over months kept clipping it shorter and shorter until one day just shaved it.
One thing to remember, and it's kind of gross (I just happen to know this because I work in law enforcement, and a lot of guys shave their head). When people first shave their head, they tend to always rub their head all the time with their hands. All day long that's all they do, is just stroke their hands on their head. Don't do this, don't even touch it. It's just like anything, if you sat and rubbed your dirty fingers on your face all day long (don't know why you would), then your face, and head, will break out. Your fingers are extremely dirty and have so much oil on them. So try and resist the urge.
Hope that's more than enough info. Just beware, the first time you sleep on a pillow with no hair it feels very gross!

After a while it feels great, especially in the winter time when the wind is blowing.