1. Take an old thick book, or collection of magazines. For magazines, you will want to glue the backs together into a cardboard or paperboard backing to give it the illusion of being a book. If the book is a paperback, glue stiff cardboard to the cover and let dry. Then you can cover this "hardback book" with cloth or wrapping paper. To cover, use regular glue as you would in decoupage (dilute, and spread evenly over the whole covering), cut a triangle for the corners and fold over neatly (try without the glue first, you can also mark the folds and places with pencil). Now hold all the pages tightly together, and use gold paint or a gold paint pen to paint the front edge (the side opposite the spine) fully gold, so that each page has a thin border of gold on the edge. You can do this on the top and bottom as well, if you like.
2. To glue down the pages, decide where you want the book open (the middle works!). Glue the bottom pages down to each cover, gluing only the last 2 inches or so in from the edge. Glue all the other pages together by holding the pages together and brushing glue all along the top and bottom edges of the pages. This should hold the pages together.
3. You can do whatever you like with the open pages. To decoupage a picture or poem on the existing writing, simply cut out the poem or picture and do normal decoupage. To antique the pages first, you can make a medium-to-strong regular black tea, and brush this onto the open pages - you may brush unevenly, "spilling" drops here and there to make splotches. Make sure you press the pages down flat when drying, or they will curl (you might want that curled look, though). Then decoupage over this, using similarly antiqued paper if you like.
4. To cover up the writing, simply use a blank sheet of paper, antique and decoupage it as above, and glue to the open page.