Hi Kickerfish,
First off, I would avoid using the flash as you are going to get a lot of extra shadows that you don't want. When you first start out, try to use natural light (sunlight) in clear conditions. You will not want to do this when the sun is high overhead, but in the morning hours or afternoon hours.
Now, as far as background, keep it clean. For dark baits, I use a light colored (usually white) background and for light colored baits, I use a dark background. Now, here's the rub...the expsure meter on your camera is going to be fooled by the color of the background.
If you can, you'll want to use a manual exposure mode so the auto function doesn't get confused. Now, here's where you need to pay attention as this will seem counter intuitive. For the light background, you actually need to open the camera up...give it more exposure...by about 1 to 2 stops, just depending. Use a technique called bracketing...shoot at the metered reading and then open a stop...shoot...open up another stop...shoot...and then go the opposite direction.
For the dark background, you're actually going to want to close down...or let less light in...by 1 or 2 stops...again, bracket.
Remember, keep the background clean! Lots of extra lines or patterns will detract from the photo!
If you have any questions, just send me a PM.
-D