Virtually anywhere would be a fine place to start. I myself normally "buzz around" a bit at first trying to locate a "hot spot". If I find it, I normally start honing in on that area pretty well. Then, I go outward from there on future hunts.
Keep this in mind...
A great many of the local parks have been hit HARD over the years. Doesn't mean there's nothing there, just, you have to be a bit more creative and work a bit harder to find the "stuff". In effect, you always have to consider the possibility that the park was hit before you got there. If it WASN'T, great, you'll have a doozy of a time. But, if it WAS (you'll be able to tell), gotta outsmart the park
Pick some spots that are tough to reach or overgrown or may even be on an incline and search these areas first. Why? We are all creatures of habit. We want the easiest, the most convenient. Most other detectorists probably run towards the baseball/football/soccer fields, bleachers, picnic areas, etc. Because they're easy. By hunting the LEAST obvious spots, your odds go up a bit.
Make no mistake, by all means DO hunt the whole park. However, I always tend to start with the out-of-the-way, tough-to-get-to, less obvious places first. And it almost always works. Try it
