A picture is worth 1000 words, so check out the photos on the left.

1. Bend the LED leg that you want to put resistor on.
   It does not matter which leg, but you should be consistent so you won't have to think when using multiple legs.  I put my resistor on the Anode (+) side of the LED.
2. Bend one of the resistor leads.
3. Hold them next to each other and stick it on blue tape or blue tack
4. Solder them together
5. Clip the excess.  8mm is about the ideal length.