I like to go to places where there aren't many "if any" people around (curious people sort of "get in my way" - especially 800 children chasing you around and "helping" you dig & find things - perhaps there is a "right place at the right time for "crowds"?).
Remember no site is ever "hunted out". I've found lots of unique items on old homesteads/farms/sports fields that were "supposedly hunted out" by others. Funny, how people drop coins, pocket items, jewelry and such everwhere and don't seem to pick them up. Most of my finds were just a few inches or closer to the surface. The ground conducts/reacts differently with different moisture & mineral content at different times. I've gone over areas where one of my buddies (who has the exact same detector as mine) has "hunted" and found things he's missed.
I never tried any beaches...may be interesting in Alaska, but I think some of the more populated beach areas in the Lower 48 would yield better results (jewelry and who know what else?).
You should ALWAYS get permission to hunt on private property! I've found lost items for folks and they were very appreciative. I was "rewarded" by their reactions & verbal thanks - never took a financial reward (feels better that way!).
Seriously, practice "plugging" (cutting around the item once you have it pinpointed - and then replacing the "plug" so it looks like no one ever dug there if at all possible) and/or using a rounded off "probe" to find your items...being careful not to scratch them. One bad scratch on an old valuable coin and you may end up with just "an old coin" instead of a "collectible". Of course most of my finds are "collectibles" to me...
When I was stationed in the Upper Peninsula of Michigan...I'd heard of stories/history of the old logging camps. The workers lived in tents with wooden floors and played cards with $5 gold coins. It had been said that the coins would fall between the slats of the boards and were "lost". I always wanted to hunt some of those sites, but never got around to it. Historical site research is a very real part of your "experience"...puts you in touch with a site, as you "hunt" - you can think about history, the people that were around those areas living their lives, "losing their valued treasures" for us to find....
Oh, and LEARN your equipment! Study the manual, listen to any tapes provided and learn how to "tune it in"...Many of the newer detectors have features I've probably never even thought of or heard of. Tuning mine to reject minerals in the ground has to be done correctly, or I'm tuning "out" items. Also setting it to reject aluminum can "pop tops" can cause it to skip over items (especially nickles and some rings).
Ok...<metal detecting babble mode off...>