I use a mane pulling knife like this one I linked, its like a comb and a knife together so it gives a much more natural look than scissors, but 'cuts' the hair so its not so much pulling. mane pulling knife - Bing Images
I use some physical object (like the handle) that's about 4" and use that to measure how far down to 'cut' so it stays even. So, I measure four inches down using the handle, cut\pull, measure some more, etc. It works pretty great.