That is a nice link.. One thing it didn't mention though that can be greatly helpful is working in proximity to a flame like a torch/candle when transferring sterilized tissue to the sterile culture.. The heat created a massive up-flow that helps keep any airborne pathogens from falling/collecting on surfaces nearby.. Ontop of that, a diy Pasteur flask will help prevent infection during the growth phase.. Not that tough to rig something similar up.. I found these practices extremely helpful when I was culturing yeast sources..