If you don't have a die-cuter, and if you do use a rotary cutter, make sure your blade is sharp. Also, change the blade when it starts to get dull.
It will make things a bit easier for you - if you decide to use a rotary cutter.
Some people swear by the June Tailor strip cutting guide. (I have one, but I've never used it) It doesn't cut anything, but it is supposed to help one make even width strips.