Most important step with any kind of patchwork is to constantly iron your seams as you go so you get a perfectly flat piece of fabric and all joins lie flat
I usually stitch everything together and on the inner side i iron the fabric to the sides, and on the front side i use a flattening decorative seam (u have it on Singer machine) it's zigzag +direct stitch together. It awesomely flattens everything and keeps the ends of fabric away from ragging... and makes the final patchwork piece even and flat.
I usually apply starch on the fabric, dry it, iron it and only after that i start cutting and stitching. The fabric is like paper afterwards. I do it with light colours only.