Hive identification. What are your methods?

[Bakersdozen]

I draw a simple sketch in my note book, of the hives position and their orientation to each other, then label them. Last year I had two yards (front yard and back yard  ). The front yard hives where labeled a b c....., the back yard 1 2 3...  . I used that to write my notes. One day maybe I'll make BeeKEEPER and I won't need that crutch  .
I annoys me greatly when I can't remember what was happening in my hives. "Was that one doing that great last week?"

That's very similar to what I am doing.  On index cards, I have a diagram of the city bees and the country bees.  With only two apiaries, that is all that is needed. An arrow pointing North on my diagram is sufficient for me.

Instead of thinking the notes are a crutch, that could be exactly what makes you a beekeeper!  Your notes will aid you learning and not to repeat the same mistakes over and over. Don't be a bee HAVER! A bee HAVER installs the bee package in the spring and expects to go back in the late summer to pull honey.   
Can't remember from one week to the next what was happening in your hives?  Join the club.  Age and memory are cruel.   :'(

[Yankee11]

I also use the cattle ear tags. I like them. You can move them around from box to box and you don't have to paint and repaint numbers on boxes.

I have also found out that by starting the number on the bottom box, it helps me realize when I have rotated brood boxes.

[Papakeith]

ear tags!  Never would have thought of using those.  Thanks!

[Barbarian]

I use tags similar to the ear tags. I make my tags from semi-rigid plastic (milk or ice cream) containers and put the number on using a permanent marker. The tag goes on the back of the brood box with a push pin.

Like other members, I date mark the top of the frames, when started in the hive, with the last digit of the year date.

I use a spiral bound A5 notebook for my hive records. I use two facing pages for each hive. I start recording the date and other brief notes at the top of the LH page whenever I go into the hive. Most entries occupy a single line on a page. The series of entries run down the LH page then start again at the top of the RH page.

[Bakersdozen]

Thanks for the picture Yankee.  I will use that one too.
I thought of this idea yesterday.  At least I haven't heard anyone mention this before.  Barbarian's comment reminded me.  Colored push pins on the outside of the hive body that match the color code on the queen.  At a glance, the beekeeper knows what year they installed the queen.  If she has been superseded, that's a different story.