While the standard, old-fashioned means of pressing and drying a flower by placing it between the pages of a book is certainly effective, it's not the speediest means to dry and flatten a flower; book pressing can take several weeks, in addition to being potentially messy, sometimes causing damage to the pages or spine of a book. For a faster way of preparing a beautiful piece of nature for projects like stationery or laminated bookmarks, press yours using paper and a conventional clothes iron.
Prepare the iron. Drain the water from the iron if it steams automatically, or set it to the “dry” setting if it doesn't. Set it to a low heat setting (somewhere in the lowest third of the iron's range). Let it heat up, keeping it in view for safety's sake.
Position the flower between two sheets of paper on the ironing board. Pay attention to the position of the leaves and petals to see where they'll land when pressed down. If necessary, stick your hand between the sheets as you press them together to hold parts of the flower where you want them. Press the paper with your other hand and slide your first hand out.
Weigh down the pressed flowers. Lay a heavy, hardcover book over the sheet of paper at the position where the flower is covered and press down to flatten it. Take care not to slide the book across the paper or the flower may get smashed and smeared.
Iron the paper to dry and press the flowers. Remove the book, then press the iron flat over the flower, heating and pressing it through the paper. Again, don't slide the iron, just press it. Remove after 10 seconds, wait for 10 seconds, then repeat (this will keep the paper from scorching). Check the flower occasionally to see if it's dry by carefully peeling back the paper. You'll know it's finished when it's stiff.