if you're starting to paint flowers, getting the shapes of the pots can be challenging. Here's a few visuals I found online that should help.
take a coffee cup or soup bowl and look at its top when you hold it at eye level. then lower it a bit and look again. You'll notice it's shape gets wider as it drops below the horizon line. Keep lowering it and drawing the top shape you see.
the top of the elipse should fit inside a rectangle or parallelogram. It should be symmetrical.
(sketch by James Gurney)
Now set up simple cup or bowl in your studio with a strong light on it. sketch its shape and color in the value pattern using grey scale markers or a soft pencil (6B)
Hope these tips help!