There is nothing more personal than finding the seat that is right for you, and how you ride.
But, trial and error (mostly error) has taught me some general rules that I think hold true for most riders.
-the part of the saddle that you are sitting on must be as wide as what you are putting on the saddle. There may be some 130 pound guys who sit on something three inches wide. But, the top surface of my saddles average close to six inches wide, because what I put on the saddle is kinda wide.
-a saddle must be firm enough that your weight is on your pelvic bones (your sit bones) not on your privates and crotch region. My favorite saddles have high, firm support platforms at the outer edges, and then are cut away or recessed in the center (such as the Specialized Body Geometry saddles).
-soft, plush cushy saddles feel great at the store, but are awful after thirty minutes. The "sit bones" sink down into the soft foam, leaving most of the weight on your crotch and privates.
-your pelvis needs to be upright in order for your weight to remain on your sitbones. Some young, flexible riders can use a bar that is three inches lower than the saddle, and still keep their pelvis upright. They do this by sitting straight up to the "beltline" and above the "beltline", their back arches sharply forward toward the bars.
-Most people do not have that sort of back flexibility. My stems and bars are set a bit higher than the saddle. That allows my pelvis to be upright, and puts my weight on my "sit bones". No more pain in my hands, wrists, arms, and necks. As a bonus, I can see more of the world than just the pavement in front of my bike.
-After you get your bars up to proper height (only people who are paid to race, pretend that they are paid to race, or who enjoy bragging about "how much they suffer" for biking truly MUST have their bars lower than the saddle), experiment with a variety of saddles to find the one that is the most comfortable for you.
-Trying a bunch saddle designs over the years led me to discover that saddles that follow the Specialized BG design, that are about six inches wide, and have firm padding, are the one that work best for me. Each time I go to a bike store, I look through their box of "throw-away" or "trade-in" saddles. I now have a lifetime supply of BG saddles, and most of them cost just the $10 or $15 throw-away box price.