I've gone through this too, in fact I have a new job this year, teaching K-8,
and travel between the K-4(Art on a cart) and 5-8(my own NICE room!)buildings.
At the 5-8 bldg., I have a seating chart. I have the kids every day, for 9 or
12 weeks, so that helps. I also wrote out each student's name on a small strip
of construction paper - a different color for each class - and taped their name
at their seat with that wide, clear tape you use to mail packages. So, for
example, when 6th grade comes in, I know that the kid at a particular spot is
whoever is listed at that spot with an orange strip, etc. I have 5th, 6th and
7th graders, not 8th, so each table has 3 different strips by each seat. So I'm
free to walk around the room, and when someone needs help, their nametag is
right there if I forget their name. ( I try not to let them know I don't know
it - in other words, don't make it obvious you're checking their tag.)
At K-4, my kids have names on the fronts of their desks, but with Art once a
week, I'm still learning some names. I know most of them by now, but sometimes
I'll get 2 kids in different classes that look alike to me, and I mix them up!
I've kind of decided just not to stress about it, since I've just got a few to
learn yet. The kids I learned first seemed to be the "trouble makers", or the
kids that reminded me of someone I knew. In my previous job, where the little
ones came to my room, their teachers had them wear their name tags for a few
weeks, (and again, I used a seating chart and carried it with me). My seating
charts are a simple map of the tables in my room, with kids names written in at
the appropriate table. It's on 8-1/2x11-1/2 paper, but I could probably shrink
it down if needed.
Another thing that helped, although I didn't "study" it as much as I could have,
was that I asked for a copy of the previous year's school yearbook. Most of the
kids are in their, and you can study and match names to faces that way.
I suppose another possibility might be to have their names written very large on
their art shirts.
Hope this helps - just think - once you have all their names, you'll only have
to learn the kindergarteners each year!