When someone gets in the ocean the cold temperature cause fingers to shrink which make rings loose. When these folks come out of the ocean, the first thing they do is shake off the water and in some cases, the rings too. This doesn't mean rings are on the slope, they can be anywhere because of the shifting sands constantly moving things around. Same for necklaces but for the most part they'll be in the water as most are lost there anyway. Your best bet is to work a tight zig zag pattern from the slope to chest deep waters. When you start finding stuff, like coins or other items of interest, tighten your pattern and work the area harder. Then move on. Truthfully, there's no magic spot or sweet area. It really depends on ocean currents and the sand movements.
Be careful out there. Be able to drop your gear when needed and don't tether anything to you that can't be removed at the flick of a quick release lever. I have everything on a weight belt and if I need freedom to swim I can just pull the buckle lever and I'm done. It takes less than a second! Ruts, grooves and berm (sand bar) edges will trick you in Florida. At Daytona Beach I walked out 20 yards to 4 feet of water and found a huge sharp drop off at the end of the bar. Be careful where you step! Can you imagine sliding off that and down into 10 feet of water while gear is tied on you?
Another worry is those dam ruts or trenches. The rip currents can erode the floor into a super huge ditch that will surprise you if your not careful. I use my scoop handle to probe sands in front of me so I can find edges. I use my coil to feel around them to see if they're deep. If you loose your balance the first reaction is to drop your scoop. The second is to step on the sharp corner of it. Basically, you'll need some water sandals or you could ruin your vacation with a few stitches on your toe. Not only that there is glass, fish hooks and other things that are far worse and could happen.
While in the ocean you find you're probing in soft sand and your feet are sinking in it, then you're in a bad spot. Chances are you won't find anything there because it will be too deep. Find the firm to hard stuff! Things don't sink fast there and are still in range for your detector.
