One of the more common causes of drain clogs and problems is the foreign object -- something falls into the sink drain that shouldn't be in there. Even if the item doesn't clog the drain outright, it can make the disposal jam or block other food waste from heading down the drain. Being careful gets you only so far; eventually you have to devise ways to protect the sink and those objects.
The most obvious way is to place a drain net over the sink hole. These are cheap mesh nets, usually formed into a closed-funnel shape, that sit over the drain opening. Anything that falls into the sink will fall into the net, where you can retrieve it. Very small bits of food can still get through, but that cherry pit that fell into the sink, for example, won't head down the drain. Note that food waste can build up in the net, so you'll have to empty it daily.
Knick Knack Box
Not everything that can fall into the sink is something that you want to fall into that drain net, though. When you've got a net filled with bits of food, for example, you don't want your wedding ring to fall off and hit that pile of goop. For rings and other items that you don't want getting in the sink at all, place a small box nearby and make that your knick knack box. Place things in the box that you want to protect while you cook or clean, like a wedding ring.
If you really want to keep things from getting into the sink, cover the entire sink. There are covers you can buy that block off the entire sink and not just part of it. These covers do have a small hole or two, to use as a way to pull the cover off the sink, but other than those, the entire sink will be closed off. Anything that hits the cover will just sit there. Some manufacturers make these covers to fit specific models of counters, but if you can't find one that matches your sink exactly, get a piece of wood and place it over the entire sink opening.
If you don't have any of these things in place yet and have dropped your ring into the drain yet again, call a drain cleaning company or plumber, like one from Plumb Care Plumbing, to retrieve the ring. After that, though, get the cover, box, and net into place.