Outside of these tangible things, the only way to motivate employees is through intangible things that tend to increase their morale and/or their desire to work hard. Here are two examples of how to accomplish this.
First, managers can create an atmosphere that makes work enjoyable. We see this very often today in the sort of creative work places that dominate internet commerce. These are supposed to raise morale by doing things like allowing workers to take breaks to play ping pong or climb a rock wall.
Second, managers might to things like creating little competitions to encourage greater productivity. These can be made in fun ways with prizes that are not significant monetarily but are things for proud employees to shoot for since they symbolize good work. These sorts of activities can make employees want to work harder.