As with most things, it's better seen in person...

when you've completed the paddle and ready to take your arm out of the water and advance it forward, retract and depress your scapula, keep your humerus as close to your ribs as possible without elevating (shrugging), externally rotate your humerus so your hand isn't flat with the water and is instead a thumb up position. 

When your hand enters the water, it shouldn't be at your Max reach  Enter earlier, and continue to reach forward as your hand enters the water ( a lot of people do this naturally).

If your having trouble doing all of these things, you'd  likely benefit from some specific stretches and strengthening exercises. Good luck. See you in the water...you should recognize me by my paddle!