Hanging a picture on your wall is considered a fairly entry-level DIY moment; hammer, nail, picture hook and voila -- a frame hangs on a wall. But to hang a straight picture you'll need to use a level.
There are different types of levels for different leveling jobs. If you hang wallpaper, for example, you'll want to get your hands on a plumb bob level; but if you think you'll only use a level for hanging pictures, look for a long carpenter's level or a laser level (which is useful if you like to hang pictures on an angle) [source: Lowes].
High-tech handyman tip: iOS and Android users with a few pictures needing to be hung on the walls can download a bubble level app instead of storing a separate tool.