From my own experience, all the advice above is right on the mark. I volunteered as a photographer for the Alberta Winter Games, which were held in Canmore this year. One of the events I chose was figure skating, as I thought it would be a fun challenge. I got to stand in the player's box, which was great because I could be at ice level and not have to shoot through any glass. I used my 300 f/2.8, which worked okay in vertical orientation on a full-frame camera. It allowed me to get tight compositions of the skaters, and not have to crop much at all. The monopod was an essential aid. I used f/2.8 aperture, and ISO of 3200 most of the time to give at least 1/1000 second speed or faster. If you're using a shorter focal length, you can probably get away with a slightly slower shutter speed. I found that it was essential to use exposure compensation, and dial in +2/3 of a stop (when shooting in evaluative metering mode). I like my ice to be bright white, and the skaters to be properly exposed too. White balance adjustment was necessary in Lightroom, but easy to do. I think the 70-200 f/2.8 would be a great lens for this sport, although you would probably end up cropping a few of your shots later on.