Many companies conduct bi-annual or even quarterly performance reviews to keep their staff on track. Before you conduct these reviews, you need to set KPIs or key performance indicators so that your staff understands the goals they are striving to achieve. Request their written reflections on how they have performed and measure their main achievements against their KPIs in order to give your staff a score out of three or five. Depending on how they fare, you can offer pay raises, bonuses or rewards on a regular basis.