How To Do Satin Stitch
Satin stitch is great to fill in areas of colour. It’s best to use just one or two strands of thread at a time, and take your time to ensure these don’t twist as you stitch so they lay flat.
Bring needle up at point A and re-insert at point B, pulling thread all the way through to the back, making one long stitch.
Bring needle up at point C and then down at point D pulling the thread all the way through to the back. It can be tempting to start the next stitch next to point B, but do go up to point C instead as otherwise your fabric can pucker.
Repeat these steps until the area is filled in.