You've got a good start with the right detector. I have had nothing but success with my Ace. My brother bought the 150 and does just as well.
Parks with sand lots or wood chips under the playground equipment are by far the easiest places to coin hunt with excellent first timer success. Plenty of clad stuff, even an occasional piece of jewlery once in a while. FOr me when I'm feeling down on my luck and in need of just any find I'll head to an old park up the road from me a ways. I will always atleast find a few cents. Just remember, its not how much money you find....its the fact that the money you find is free and its addictive finding free money with your metal detector, especially the older stuff (pre 1965 silver coins).
Check under the park benches where the parents typically sit and watch their kids. Its amazing the stuff people loose out of their pockets there. By the way, incase you havn't noticed yet with the machine, the closer you get to the metal playground equipment bars the more the machine falsely alerts due to the metal. Compensate by turning the sensitivity way down. You loose some depth but odds are keepers are not that deep anyways.
Lots of luck to you and don't forget to research.