Shown is a very helpful gadget I made to assist in soldering resistors to LED's.  It is made from 2 Radio Shack alligator clips, 2 wood screws, and a hunk of wood.  This device will hold the components in place while I solder them together.  They sell something like this at RS called "Helpful Hands", but they were out when I went, so I made my own.

When soldering resistors to LED's, it doesn't matter what side the resistor goes on.  I usually put it on the long lead (positive lead).  This lead will go to the wire connected to the + side of the D1 holes.