Very fast wing beat, lower to the water than say Malls. In proportion to their body their necks are relatively long and short butt compared to Wood Ducks, which also fly fast. Woodys have a shorter neck and butt that stick out.
Teal seem to fly more erratic and quicker than you'd imagine. I think of them a mini F16 fighters coming for a fight.
They're also probably the smallest ducks you'll run into in your area that time of the year anyway.
Here is a link to 1 site I searched and found. You may be able to find better.
http://members.cox.net/azwildlife/Identifywaterfowl.htm#Blue-Winged%20Teal
Good luck!