Since you're only going one block high, it probably won't be too bad.
I can give you a few tricks my uncle showed me when I started my foundation.
Square up first going corner to corner, and snapping a chalkline for your rows (outside edge obviously).
3-16" blocks = 4'. If you do your 24' row first, you won't have to intentionally break any blocks (although, you might have to trim the ends on your last 2 or 3 to get your final spacing right, or use a $2.79 masonary blade for a circular saw if you don't have a brick chisel).
Use a liberal amount of mud starting your first row. When you have the block in place, and level, you can clean up a little, but don't sacrifice strength.
Getting the block in place without the mud sliding off the ends of the block you're setting into place can be frustrating sometimes. I was told "Type M" Portland cement has some agent added to it to make the mud a little stickier, but I used pre-mixed Quikcrete mortar.
It might not hurt to use more mortar than necessary while learning, but it makes it harded to squeeze the blocks together to get your 3/8" gap right. Your most useful tools will be a trowel, torpedo level and hammer/mallet.
Get your corner blocks in place and let them dry for a day if time allows. Make sure they're square and level. Then just hook the line leads to them. Now you have a chalkline, a string line, and a level to tell you where the block goes.
Also, if you have a transit, use the last couple of rows (or in your case, row) to make sure your elevations are dead on for the walls. It's easier to squeeze a joint thinner than make it thicker.
All in all, you'll probably find the hardest thing is keeping the mud just wet enough. It always seems to go from too wet to too dry really fast for me.
I've done almost 500 blocks in the last month (2 hours here, 4 hours there), and I'm still learning.
