1. Put a small drop - about the size of a capital O - on the bottom (if doing 2 per slide) or the far left (if doing 1 per slide) of the slide
2. Hold a second, clean slide at about a 45 degree angle and BACK up into the spot of blood.
3. Pause, and let the blood spread by capillary action across the slide.
4. With a smooth motion, push the spreading slide toward the end of the other slide, running off the top, if necessary.
5. If doing 2 smears per slide, flip the spreader over to make the 2nd smear.
6. Let smears airdry, then fix in 100% methanol for 1 minute.
7. Dry again, typically overnight in a ziplock bag with dessicant.
8. To pack for carriage/shipment, place slides in empty box with a piece of index card or paper between each one.

Here is a movie showing how to make a smear.

For lots more info on techniques for studying vertebrate blood parasites, see http://www.uvm.edu/%7Ejschall/techniques.html .