To finish off your pretty flowers you need a center a French Knot. This also is very handy for tying knots at the end of your thread.
Step 1: Come up and wrap thread around needle twice. You want to keep your needle fairly tight to the fabric and your thread tight on the needle.
Sep 2: Holding thread snug, go down and pull thread through.
Finished!
It may take a little practice to get them looking right. Remember to hold your thread snuggly.