Stand close to the wall and look down it. Occasionally, with the reflection of light against a painted drywall, you will be able to see the indentations of the nail heads. A magnetic finding device may help you locate the nails. Once you have located one stud, measure 16 inches in either direction to see if you can locate another. Then measure to where you want to hang your item to be sure that you have the support of a stud.
Some walls are load bearing, while others are non-load bearing.
Load-bearing walls help support the roof and thus, support the entire house. Before you decide to remove or even cut a large opening in a wall, determine whether or not it is a load-bearing wall. To do this, climb up into the attic. If the joists or rafters are perpendicular to the wall, you can be fairly sure the wall is load bearing. A hole or a crack in the wall.