If you're determined to slip the first stitch, I would use this method
. It does not matter that your edge stitch is not always the same type (ie. knit or purl), the first and last stitch of the row are worked a particular way no matter what.
I want to caution you about doing it though (from my own experience)......ONLY do it for edges that will be seamed to a like edge. So for example, it is a great method for the sides of the front and back, but only
up to the armhole. From there, with the sleeve shaping - and eventually having to be seamed into the armhole, slipping stitches does not make it easier, in fact it makes it a lot harder. When you slip stitches, you end up with half as many loops along the edge because those stitches are only being worked every other row, and when seaming in a sleeve you often need those extra stitches to ease it in properly.
Hope that wasn't confusing.....bottom line, for anything being seamed to an edge that's exactly the same (sides of a sweater or the length of a sleeve from cuff to armhole, etc.) , it is a GREAT method and does make seaming easier and faster.