Follow the Pareto principles (80/20 Rule) - According to this rule, 80% of the effects come from 20% of the causes. 80% of the things you are doing on your job will produce only 20% result and other 20% things you are doing on job will produce 80% result. Try to find out which 20% activities are most important and spend most of your time doing them in the better way. By applying this rule you can perform better at your job and also ask for the pay raise.
80% of your sales come from 20% of your clients. 80% of your complaints come from 20% of your customers. 80% of your profits come from 20% of the time you spend.