There are many ways to improve the cooling power of your refrigerator. Try cleaning the coils first, as this is a common problem behind low cooling power. \
The fridge should optimally be set at 37 degrees and the freezer at 0 degrees. Check these settings to make sure everything is at the right temperature. \
Shift items around in the fridge so that there are at least two inches of clearance for every wall of the fridge. Nothing should be right up against the walls to ensure proper air circulation. \
Check the seals. These squishy parts of the fridge often break down and wear down over time. \
Place a dollar bill in the door, closing the door with the bill half in and half out of the door. Try to move it. \
If you can move the dollar easily, you need new seals. The cool air is leaking out around the seals and that's why the fridge isn't staying cold. \