For most homeowners there is nothing scarier than having to hang stuff on their walls. Except perhaps, having their basement spontaneously fill up with blood. That'd be pretty frightening, but only slightly scarier than putting a hole in drywall. And FORGET about hanging stuff on plaster, that's right up there with finding out the retired neighbours next door are putting on a massive glass addition to accommodate their weekly nudie parties.
I understand your fear. You don't know what size anchor to use, you don't know what size drill bit to use for the anchor you can't figure out. It's a never ending circle of confusion. Almost makes you wish your basement would just fill up with blood so you could make an insurance claim, sell the place and move into a house that already has nails in the walls.
I haven't figured it all out, but I think I can demystify the "how to hang it" dilemma for those of you who are worried silly by it all.
Have a look see.
How to Hang a Picture
How to use anchors and other picture hanging devices.