I want to layer, irregular "ground" strips and I keep getting pooches (the fabric seamline doesn't lay flat). Does anyone of you have any tricks to help me out?. I just removed the applique and pieces to begin again, and don't want to fail this time.

Thanks,
Miccie

A little basting can go a long way here. If the hills are steep, clipping a bit can help ease them in better. Depending on the look you're after, fusing or decorative stitching can be an option too.

It is very difficult to stitch irregular pieces by seaming in the normal manner, ie if your fabric is an outward curve you have to bend it and stitch it on an inward curve so it will lie flat when you open it out.

One way is to draw a line the exact shape of your piece and then shape the piece to fit along the line. It would prob be easier to turn under a small seam allowance (if you're worried bout raw edges) and top stitch the piece down or use a decorative stitch as Moonpi suggested.

Water soluble glue stick is great as a temporary hold for hloding down a piece untill you've stitched it.