Skipped stitches check list
1. tension of quilt
2. needle position(installed incorrectly)
3. old needle
4. needle to small
If all else fails it could be the machine
5. machine timing
6. needle bar alignment(mine somehow shifted on me once, and was touching the plate as it passed through to the bobbin area)
When I quilt batiks I use a product called Sewers Aid on the thread. It lubricates the thread allowing to pass through the layers easier, but doesn't stain. I know some quilters will say don't use this but I think if Sharon Schambers can dip all her thread in mineral oil, its safe. I do this with all my thread and it has helped considerably with alot of issues. Here's a link to Sharon doing this.
http://westmichquilter.blogspot.com/...-schamber.html