Having ignored most warnings about using knit fabrics, I decided to try making a summer dress with jersey fabric as my second major clothing project. I did choose what seemed to be a more stable type of knit - interlock - which wasn't too hard to work with, but it did make the project somewhat bulkier than intended. I used Simplicity 3503, view D.
I wish that I had taken pictures all along, because this ended up being somewhat of an epic project. I had decided that I wanted shoulder straps rather than a halter, but aside from that, followed the pattern as written. After reading reviews on patternreview.com, I followed suggestions to use a smaller size than called for on the pattern, which was a good thing--I still had to trim down the width of the skirt.
When I was finished, the midriff band ended up looking bulky and unflattering. I was disappointed, but decided to take the midriff out and try turning it into an empire waist, simply attaching the skirt to the bodice. That just looked like a sack, so I did a little gathering here and there, till I thought it looked okay as basted. When I sewed it up on the machine, though, all of my gathers got pressed out, and we're back to wearing a knit sack.
At that point, I was nearly ready to give up, but decided that what the dress needed was something in the middle to give it more definition. I picked up one of the midriff pieces, folded it in half, and made it into a band to put over the seam between the bodice and skirt. The first attempt failed (I didn't measure carefully and cut the band too short.) Luckily, I had a second piece to work with, and with careful measuring and pinning, I think I salvaged the dress from the scrap pile.
Please let me know what you think. This is my first attempt at altering a pattern, so comments and advice are welcome!
Front:

Back:

Original pattern:
http://www.simplicity.com/images/product/medium/3503.jpg