I needs me sum! My latest NGD features pix done by myself and by a pro...and you can guess whose look the best.

Anything you can suggest to make my NGD threads look better would be greatly appreciated.
Polar bear rug, nice fire in the back ground, like this

If the weather is nice pictures outside are hard to beat because of the natural light.
Better light. It's almost always about better light.

Sure there's composition and focus, resolution and balance, but lighting is the most important thing.

Going outside is a good idea, especially when you can get a slightly overcast day when it's bright out but there aren't too many hard shadows.
There's a period of time around dusk and also dawn called the magic hour. The sun is up but the light is soft and at a low angle. Good time to take a photo outdoors.

Indoors - you need to add more lights. Even if the room seems bright, you generally want even more light than that. Avoid single bright spotlights because that's just going to create dark shadows. Instead you should aim the light at a wall or perhaps a piece of white poster-board and let it reflect off of that surface.
You should also remember that you can (and most of the time should) use multiple light sources coming from different angles. If you've got a bright light on the right, then get another bright light on the left.
Pay attention to bulb reflections. Sometimes they're cool to have in the photo, but other times you might want to get rid of them.
Good advice so far, you can also use a flash and bounce it off the ceiling.

Usually guitar pictures will work best if you place the guitar at an angle so it won't reflect directly into the camera, and try not to put it against a background close to the same color as the guitar. I would avoid a bright white background, but it may work well in some cases. A small angle, 5 degrees or so, is enough to avoid reflections. Play with lighting and positioning, you can get some really interesting shots.

Strangely enough, I've been a photographer for over 30 years and never really did much guitar photography, I'm mostly into birds and nature, the only guitar shots I've done were for band promo shots and some shots for ID purposes if anything gets stolen. Including close ups of serial numbers. I used a flash pointed straight at the guitar, and avoided reflections by simply putting the guitar at a slight angle, same as avoiding red eye with people. Look a little to the left or right of the flash and no red eye. Same for guitars...
I was also a professional photographer for 30 years. Today I did these shots of a friend's SRV "Main" reproduction: http://www.gunshopfinder.com/main.html I used window light, keeping the guitar just out of the direct sun, but still getting enough "punch" from the sun to illuminate the wood specks in the curly maple.

Absent real lighting equipment, I like using light from large windows because it gives the product some highlights and shape. Fill can come from white cards or even typing paper taped to sheets of cardboard.

Bouncing light into the ceiling is good if you want a very open feel to the light.
Find a spot in your house with really good light (probably where light comes in from two separate places, like a corner with windows on each wall). Also helps to have a good camera (obviously). If you do wind up using the iPad, a lot of people forget that taking a second and tapping the screen right on the object will allow it to adjust brightness, focus and stabilize the image for a great shot.