The best type of room is one that is not too humid and is about 70 to 75 degrees. To protect against debris from getting onto the finished piece, the room should be free from dust. You might even consider mopping the room or covering the floor with paper. Make sure that the surface to be varnished is clean, dry and free of any finishes.Try to have the piece horizontal. In addition, to mix the varnish, stir it. Don’t shake it, because air bubbles can get into your finished piece.