Sparkfun sometimes posts very useful tutorials on skills related to tinkering with electronics. This time they made a video tutorial on using a stencil to solder SMD components on a PCB. I find it quite useful, even for very small volumes (starting 5-10).
If you are not the lucky owner of a laser cutter, there are many websites that offer to produce the stencil for you like www.ohararp.com for reasonable prices.