The Antique Drapery Rod Co. has diagrams showing all kinds of different canopy arrangements, and the hardware you'll need to create them.
An easy way to get the canopy bed look is to hang curtains from an L-shaped drapery rod that's been mounted to the ceiling. In this case, the curtains can't be drawn around the bed, but you definitely get that romantic look. I love how, in this example from the HGTV Dream Home, the ceiling above the bed (and the wall behind the headboard) have been painted to contrast with the rest of the room. It creates a sort of optical illusion where the ceiling above the bed becomes the canopy.
There's also the option of hanging curtains only over the head of the bed. I'm partial to the setup on the left (from Traditional Home) because it only requires mounting a u-shaped rod on the wall above the bed. The arrangement on the right is a little more complicated, but with a big dramatic payoff. (From Traditional Home via This Is Glamorous.)
From Better Homes and Gardens: drape a piece of fabric over two swing-arm curtain rods, mounted on either side of the bed, for a super-easy canopy.
You can mount a single hoop or curtain rod to the ceiling in the middle of your bed and drape fabric from it over the ends of your bed. This works best if the long side of your bed faces a wall, and if the headboard and footboard are roughly the same height. (Left: Apartment Therapy, right: House & Garden via The Inspired Room)
I love the look of these canopies. I always wanted one growing up because I thought only princesses had them. They are so simple so create. My favorite is the one is in the Kelly green master in the HGTV Dream Home. I love the sense of privacy a four corner canopy gives this space. I would close the curtains and stay in bed all day!
Now that you are full of ideas, time to start deciding which one you're going to try.
Pinterest is a great tool to browse to bed creative ideas.