Tips for photographing flowers?

Any tips, suggestions, guide lines etc

I use a dslr camera, nikon d3100 attatched to a 18-200mm

I also use a pentax film camera.

Try to get the right angles and lighting. You can get really good flower shots easily.

Look for different perspectives- don't just shoot looking down at the flower. Get down to its level or below it, use manual focus to select sharp/blurred areas. Shoot in early morning or late afternoon for soft, rich light. Think of utilizing the frame space as a means to what you are trying to say, with no distracting elements- 90% of good photography takes place before the shot. Carry a small water gun or spray bottle to create drops on the petals. Look on this site and click the book covers to see amazing nature shots- He does all this in camera, on film, with no computer editing. He'll blow your mind:

http://www.freemanpatterson.com/giclee_prints.htm

To add to the excellent answer Hugh gave you: You may want to invest in a good macro lens as soon as you can. These can run a fair amount of money so start saving now. Set you current lens to around 80mm (mimics normal or 50mm on SLR). Get low and consider the background carefully. Try to fill the frame with the flower - junk behind it and dirt below it do not make for great photos. Consider carefully the shape of the petals, the leaves, and use them to graphically enhance your composition. Use a shallow depth of field - open as wide as the lens will go at the 80mm setting. You may want to play here - shoot one image as wide as possible (probably around 5.6, but I'm guessing - I don't have Nikon gear so don't know the lenses), shoot the next one 1 stop smaller, i.e. F8, and so on - look at what comes into focus when in the background. This will teach you the depth of field range at that setting (80mm) for that lens - this knowledge comes in handy, and flowers are the perfect subject for it. In addition to using the spray bottle (gotta have it), shooting at first and last light - try to get the light behind the flowers so it shines through the petals. If you need some fill light use a small white card which you can hand hold to bounce some light into the flower itself.

Have fun, I love shooting flowers and don't care that people badmouth it. I sell a lot of flower shots.