I wasn't very happy with how I'd started each thread - with a knot, but then the table cloth was one of the first project I'd done satin stitch on besides woolen thread on canvas for a Christmas tree mat. As I picked it up again and finished the table runner, I'd learned to fasten the thread in the cloth a ways away, and then pick it out and fasten it in the embroidery once I'd finished the thread.
By the stems, do you mean the light green lines going from flower cluster to flower cluster? Those are just a double row of stem stitches. To quote wikipedia, "stem stitch, in which each stitch overlaps the previous stitch to one side, forming a twisted line of stitching, with the thread passing below the needle. It is generally used for outlining shapes and for stitching flower stems and tendrils."
The sharp corners are thanks to my Mom on the table cloth, and thanks to me on the table runner. I hemmed them with lightweight linen thread leftover from my head linen. It was just a matter of anchoring the stitches underneath the line of dark green stem stitches I'd already sewn.
And thank you for the compliments on my embroidery. I am still learning, but practice makes perfect, right?