working with the sandwich is good, there are times mine works perfect on the sandwich and still messes up so just hang in there. we all have to "rip" but it's a learning experience. just take is slow and easy, if using the walking foot, let the foot pull the fabric through just make sure it isn't dragging or getting caught on something. I've been doing this for about 20 years and I "unsew" a lot on a project.