Read and heed this article, paying special attention to the section regarding cable housing preparation: http://sheldonbrown.com/cables.html
Consider investing in a high quality cable cutter; Park and Shimano are excellent, FELCO are top dollar but a worthwhile investment if having and using the finest tool is important to you.
A "fourth hand" tool is fairly cheap and is handy for tensioning cables while you clamp them if you do not have a helper available.