Maybe a mod can move this thread?
I hated sewing elastic when I first started sewing dipes. Here are some things that made it easier:
1. Use wider elastic - I think 1/4" is too narrow and just doesn't have enough "oomph" to gather many layers. I use 3/8" and might even use the next size up if I had really heavy fabric layers to gather.
2. Leave a "header" of elastic above the point where you first tack it down. Use this header to pull the elastic taut from both ends as you stitch down the length. After you've tacked down the other end, snip off the extra. It wastes a little elastic, but hey, it's cheap and it really helps get the stretch nice and even.
3. You don't need a 3-step zigzag - plain ol' zigzag will work fine. Make sure your stitch width is set wide and length is set to match. The stitches shouldn't be too close together or the elastic won't have enough room between stitches to spring back to it's relaxed state.
Hope that helps!