If you realize that your walls have cracks, you only need a few tools to repair them. The cracks usually occur when you bump something against the walls, after a natural disaster or when your home is naturally settling on the foundation. If the walls are cosmetic, you can make them look more presentable. In some cases, the crack indicates that there is damage on the joists or studs in your house.
Before you start repairing, determine whether you have a drywall or plaster wall. If it is plaster, you need to apply plaster paste to fill in the cracks. Make sure you sand and paint the area once the paste dries.
For a drywall, you will be required to use spackling putty to fill in the cracks but unlike the plaster one, you have to apply the putty twice. It also has to be sanded once the cracks have been filled in.