Close the doors when you are not actually getting something out of the refrigerator. Reduce the amount of time you spend looking for something in the refrigerator while standing in front of it with the door open. If you frequently open the doors or leave them open for extended periods, you're making it hard for the unit to cool.
Wait several hours after adding a large amount of food to the refrigerator for it to get back to the right temperature. When large amounts of food are added to the refrigerator, first the cold air spills out of the refrigerator while you're adding the food, and then the refrigerator has to lower the temperature of the food. As a result, it takes hours for the refrigerator to be down to the right cooling temperature again.
Adjust the temperature control for the unit by turning the control knobs to cooler settings. If either knob is moved to the "Off" position, the refrigerator will not cool. The factory preset setting for each knob is the middle setting. The knob labeled "Refrigerator" controls only the refrigerator side, while the "Freezer" knob controls only the freezer side. When you make adjustments, move just one increment colder at a time. Check the temperature again in 24 hours. If it is still not cold enough, move an additional increment per 24-hour period until you reach the temperature you want.