Screws and screws with masonry anchors for heavy items are your best choice for hanging things on plaster walls without picture rail.
Hanging pictures on lath plaster wall.
The best option mostly depends on the weight of the picture in question.
For lighter items simply screwing into the plaster with a 1 1 4 drywall screw is usually enough to get the job done.
If the pictures are small and equipped with a wire on the back use a small picture hook and nail.
Adhesive picture hooks are the best way to prevent damage when hanging a picture but pre drilling the hole will usually prevent cracks and chips from forming as well.
Plaster walls have a tendency to crack and crumble if you attempt to hammer a nail directly into the wall.