DIY lightbox

Here is the DIY lightbox I made last night. I found some tutorials online and decided to go for it. I've been thinking about buying a lightbox, however they can be costly. I thought I would go this route first. It was fairly inexpensive, and super easy to make. I'm having a hard time achieving a quality photo though. I'm doing something wrong here, I just can't figure out what it is. My camera doesn't come with too many instructions for different shooting scenarios and I have already had to change the batteries twice due to the flash eating up so much energy. Any suggestions?

UPDATE:

It's a couple of days later and here are some results from the lightbox. I can't get the white background I want on the clothing items I am placing in there. I don't know if I'm using the wrong lights or they are positioned wrong or what. But, when I take close-up photos of my husband's phone, it looks really good.