Don't do another thing until you go down to the local paddle shop and buy yourself a copy of EJ's Rolling and Bracing dvd.
A million people can chime in, but bottom line, if you watch that dvd with your paddle in hand in front of your TV, you will be rolling like a champ in a matter of minutes.
Practice in your local pool before getting on moving water. A very different experience...
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body. But rather...To skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming... WOW !!!! What a ride!!!!!!"