Water your grinder frequently. I often tell students to add water to the grinder and have them tell me that they already did when class started. Water gets used fairly quickly as it sprays off of the spinning head and also coats each piece of glass that you are grinding. You lose water every time you remove a piece of glass from the grinder so it doesn't take long for the level of water to drop below its optimal level. Your grinder head will last far longer if you maintain water in your grinder. Any time you see a powdery build up as you grind a piece of glass, add water!
Speaking of water, Shawn's Octagon Diver Window really made a splash in class because everyone who saw it loved it. The iridised blue that she used gives the water a shimmery, pinkish tint that doesn't distract from the subject matter but actually turns your head towards it. What's not to like about this?
Melissa is back and her Butterfly and Iris Window is really taking shape now. The Iris is still a bit sketchy but trust me-- when it's ground and pinned down to the pattern you'll have no problem realizing what it is. Look at how nice and symmetrical her Butterfly's wings are even though they haven't even been completely ground yet. That's the kind of detail that I like to see.