Remove all of the pipes and fittings from the water pump and look for any signs of clogging in the inlet valve or suction line. Run cold water through the pipes and water hoses to ensure they are not blocked and their lining has not collapsed. Cleaning the mechanical seal on the body of the pump with a cloth and light cleaning agent can help remove dirt or debris that can affect the efficiency of your pump.
Replace the elements you've cleaned and be certain they are all connected correctly before turning on the pump to check all pipes and values for any signs of a leak. The pressure of your water pump will be greatly reduced if any water can escape, so it's important to carefully inspect the water hose. Examine the air pipes because air entering the system also can create problems. Take a look at the valves that connect the pipes to your pump to ensure they're not worn or faulty. The efficiency of your pump will be greatly improved by replacing any old or leaking parts with new materials that can be purchased from a local plumbing supply store or online.
Ensure that your suction hose is not longer than it needs to be, thus reducing pump capacity. This will cause your pump's engine to work harder and use more energy than necessary. Cut your hose down to size or purchase a replacement hose.