• Make sure your candles don't interfere with sight lines across the table. I usually associate this rule with flowers, but of course it's true for candles too; if your guests have to crane their necks around tall tapers to talk to one another, you might want to move those tapers over to a sideboard.
• Locate candlelight at different angles around the room. Try to do candles in other spots, not just the table; candlelight coming from different directions will add soft light throughout the room. Set up candles on your buffet or bar, in wall sconces, or along a windowsill.
• (Almost) anything can be a candle holder. Take a look through your storage and see what you can find. As long as it's not flammable, you're good to go. I have a set of old copper measuring cups from a French flea market that doesn't do any good for baking, but they're gorgeous tea light holders. Glass jars are of course always nice, and you can dress them up with a little ribbon or greenery. If you have simple glass votives or yogurt jars, you can also tuck them inside shelled-out gourds or fruits.
• Try a mirror to reflect the candlelight. Set out a collection of candles in different sizes along a mirror. This will enhance the softening, flickering effect of the candlelight.
• When in doubt, toss some tea lights on a few saucers. Tea lights are incredibly inexpensive, and they do the job for a single evening (sometimes longer). Clusters of them on pretty china or glass saucers is all you really need. If you want to dress them up, you can make little cuffs for them out of narrow ribbon (see first photo, second row above).
For some more candle inspiration and resources, try these posts:
• Best Tealight Votives
• Outdoor Lighting Inspiration: Use Lots of Jars
• Easy Entertaining Trick: Mix Colored Candles
• Flickr Finds: Candles in the Garden