"Straight stitch can be quite effective! By fanning out straight stitches from a center point and making their outer edge a bit jagged, you can create a pretty nice embroidered flower.
Refer to these diagrams and instructions for the most common embroidery stitches for your projects.
Embroidery Stitches for Beginners Beginners' Silk-Ribbon Embroidery: Five Easy Stitches - Threads
'Learn to Sew: Basic Sewing Machine Stitches.' (via eHow)
Hand embroidered tree with blossoms by Mary Corbet The embroidery on the tree consists of three stitches: split stitch, straight stitch (or tiny seed stitches, sometimes doubled), and French knots.