Mollys are good. Toggle bolts, also pictured above are better. My preference, depending on location of the object ot be hung, is to mount a board horzontally to the studs and then hang the hanger on the wood.

This does not work well in the family or living room but works great in the garage.

A good stud is hard to find

Sorry I couldn't resist

only if you are looking in the wrong places

You could always use a stud finder.

not really. just look for an area thats a lot denser than the surrounding area.