1.Use brown kraft paper and painters tape. Cut out the paper the size of your pictures. Use the painters tape to attach them to the wall temporarily in a layout you like. You can also lay them out on the floor to start with
and re-arrange until you get something you are happy with. Once the paper is on the wall put in your nail at the centre of each one and then remove the paper. You are now ready to put up your masterpieces!
2. Use a product called "Hang & Level" which is available at most home improvement stores. You hang your picture on it and place it up against the wall at the height you want. Remove the picture and push in the tab which leaves a mark for your nail and away you go! It will be leveled and will eliminate those multiple holes in the wall ( I used to be a fine example of those people!)
3. Make sure you use the correct hanger for the size and weight of your art. (Once you get them up there you don't want them coming down!)