Keep in mind that the older the sight, the more that coin meant to it's owner, and the less likely he (or she) would have been to drop it. You may not fancy digging up clad coins at a playground but it is a good place to start. You will get experience pinpointing and IDing targets and can develop your technique. When you go back to the more difficult sites detecting will be a bit easier.
I don't know how thoroughly you read this forum, but twice this week I hunted an old mansion. Day one I found 4 wheats and a bunch of relics. Next day I found 3 or 4 clad coins from the 1960s and a bunch of relics. 5 hours hunting, 8 coins. Not the style of hunting I usually prefer. I dream of finding 100s of seated and Barder type coins and stacks of Morgan silver dollars but I also realize that pounds and pounds of clad coins can be used to buy these things. Ask John. That, and even with the type of hunting I prefer I get a nice old coin every once in a while and more than my share of jewelry.
I hope this helps. Keep at it. You will get better before you know it. At least 75 percent of MDing is technique.
Chris