Quote taken from this site.
This is the press making information and general tutorial we used to make our flower presses for this week's handicraft. Each family made a press, and each child made a card using a pressed flower I had done ahead of time.
This one is also a lovely tutorial!!
Instead of phone books, we cut 5 sheets of cardboard to layer inside, along with paper towels to lay the flowers on inbetween the cardboard. Water color paper would also work instead of paper towels.
Our flower presses are 10x10 in. and the cardboard inside ours is 8x8. The 3/8 bolts are 5 inches long.
Great instructions for applying pressed flowers to paper can be found here. We used glue sticks and contact paper for basic supplies.