I've been cutting in my own systems for close to 10 years. It's a little intimidating at first starting off with a long mop of hair but as you gain experience it's becomes pretty easy. I scissor cut my system while it's on my head because I've been doing it that way from the very beginning. Scissor cutting gives a nice layered look. Seeing layers makes the hair look natural. It's best to go little by little gradually cutting the hair down to the desired length so you don't make a mistake.

In other words don't go for a precision cut right off the bat take your time. Once you get the hair cut down to a manageable length it starts taking shape. One technique to shorten the overall length is to wet the hair and pin it up on top then bring down a thin layer all around the head and cut it to the desired length. You then bring down another layer and the first layer you've cut gives you a guideline on where to cut the second layer. You continue bringing down layers until you've shortened up the overall length. Then you're off and running.

Once you've layered out the hair with scissors or a flowbee using a razor comb is good for tapering down the hair on the sides and back where the systems hair meets your own natural hair. Razor combs are excellent for blending and thinning the hair so you don't see cut lines. I don't recommend using a razor comb to cut in your entire system because you want to see the layers and scissor cutting or a vacuum hair cutting machine would provide that.