First I turned the jeans inside out and layed the jeans on the floor. I layed a pair of skinny jeans that I already owned on top of the jeans I wanted to convert and lined them up to the inside seem so I would only have to sew and cut on one side. I drew a line to trace the skinny jeans and pinned the two pant leg layers together.
I then sewed a straight stitch over top the line I drew while tracing the jeans, and reinforced the line with a zig-zag/straight stitch combination. (Sorry I don't know the proper stitch name. Refer to picture.)
I turned my jeans right side out and tried them on to make sure they fit good before cutting off the extra material. I was happy with the results so went ahead and cut it off.
They aren't perfect but if you aren't looking at them really close you can't tell. Now I can wear them with my boots and with flats! Yay!