Use a filament cleaner! That it the biggest tip to avoid clogged nozzles. Sponges, foam rubber, cotton pads (don't use cotton balls, as they might cause clogs) have all been used, but my favorite is a piece of paper towel wrapped around the filament and clipped or tied. When the filament is pulled through one of these on the way into the extruder, it wipes any dust off of the surface of the filament and keeps it from being carried into the extruder. You don't want this dusk building up in your nozzle!