Looping/knots on stitches
To prevent looping and knots forming under the start of a seam, hold the thread ends firmly or first stitch over a small piece of fabric folded double. Then place the fabric to be stitched right next to the folded fabric piece under the presser foot and stitch. Don’t forget to secure the seam start and finish with a few back stitches. Trim off the little folded fabric piece.