entertainment - The retirees often called it having "it," though you can't really define what it is. Ray Stevens had it, Johnny Valentine had it, and a few others over the years. I'm not gonna try to hold people to that excellence, but being able to entertain is often the name of the game. A great ring general knows how to use psychology to work the crowd and two awesome workers can entertain with straightforward wrestling. Nowadays that's a rarity and I hate to penalize today's stars because they often have little to work with in there. I am looking at everything that gets the crowd into the match, except selling does not have priority here, though it is judged. Comedy wrestlers and talkers (who aren't great wrestlers) roles are taken into consideration and they are graded appropriotely. The key is overlooking their heat to see how they can just get the crowd up.
example - The Rock, some people may say he's the most entertaining, but he really is not. Being insanely over as he is from his interviews is a positive, having a big pop is a positive, having mega-heat during matches is a positive, and having the crowd cheer his often redundant in-ring work is a positive. The Rock is perfect for the WWF and is able to get the crowd to get up to a level that few can, though his heat has a lot to do with it, I would give him a "10."

selling/bumping - This is a major part of wrestling and it is ideally to be atleast passable in one or the other, if not both. Each has different levels of importance to various styles. Selling is especially important in more realistic styles, such as Japanese strong style, shoot-style and joshi. Even though it sometimes less emphasized, selling is a must. It puts over the other wrestler (which is a good thing) and if done properly can add great drama to a match. It is perhaps the most important part of ring psychology because if one over-does it they seem like they're being squashed (assuming they're not) and if one under-does it they look invinsible and it really destroys the suspension of reality. A few things of note: facial expressions, accurate and consist to "hurt" area, how well they recover (not too fast), and extra emphasis (selling after the match, taking a timeout, having it effect offensive moves, and stretching/rubbing/etc.). Bumping is different because it is style specific. Strong style and joshi use more dangerous bumping. Lucha libre and WWF-style is best with a lot of small bumping and a few big bumps thrown in. Garbage styles love BIG bumps. Ratings are gauged by what style the person competes in (usually) and how well they fill expectations.
example - Toshiaki Kawada, in addition to being one of the best workers, he is perhaps the best seller in the world. After years of putting over Mitsuharu Misawa from his elbows to his Tiger Drivers, Kawada is a master of selling. It adds a realistic element to the match that makes the tight style of Japan seem that much more realistic. He stumbles around, his facials are very believable, and on and on. Everything trick in the book is in Kawada's making him the best. He also takes all the powerbombs and suplexes that involve dangerous head-dropping and takes them well. I'd give him a "10."

heat - This is another part of having "it." The best heels can pop a crowd no matter how dead they seem to be and draw heat the best by doing the most dastardly acts. The faces are the ones who reap the benefits of their ability to sell a beating and make an interesting comeback. Like many of the ringwork rating, this is a case-by-case thing as if someone is presented poorly by bad booking they will have inadequate heat, which must be judged.
example - Chris Jericho, a guy who was extremely over when he debuted in the WWF in `99, but false starts to pushes have really hurt him. He has tried being a heel, like when he first came in, and got huge pops. Eventually he became a face and when he won the WWF title was definitely way over. I would currently rate him at "7."

carrying - This one is totally different than the others as it is kind of like ratings under 5 are almost like negatives, while a 5 is neutral, and over 5 is great. This has to do with how a wrestler deal with others above and below their skill level. 0-1 means they needs to be carried and often the best cannot do much with them. 2-3 still means they still need to be carried, but good matches are capable if they are put with the best. 4 means they carry themselves, but not very well. 5 means they can carry themselves, no more, no less. 6 means they can carry themselves reasonably well. 7-8 means they are capable of carrying others reasonably well and can have excellent matches with people on their level or just below. 9-10 are the elite, those who have consistantly above average matches with anyone who steps in the ring.
example - Yuji Nagata, many consider him the best kept secret of puroresu as he can carry the most inadequate wrestlers to their best matches. Unfortunately he is so good at it New Japan has made him put lesser wrestlers over for years. It has everything to do with workrate and the ability to make stars out of people. The best carriers are often the ones putting more charismatic stars over, but wrestlers like Nagata are a wonder to watch. I would give him a "10."

push - An important part of wrestler's career at any point is how much they're pushed. It demonstrates a level of trust in them based on past success or potential future success. Rating a wrestler's current push is hard because some people are pushed hard one minute, then forgotten about the next or vice-versa. I try to take into account how much trust is put into a wrestler, especially if their in-ring work is shabby. People are gauged by where they are on the card, on TV, etc.
example - Big Show, one of the WWF's most interesting stars. Due to his 10-year contract and inability to turn into the "giant" star the company intended he's fallen into a weird state. He was pushed at first, but kept in check with losses to the top stars. Then he dropped down into meaningless feuds, then they ditched his program with the Big Bossman and gave him the WWF title. After a time on top he was dropped down yet again finally he was sent to OVW to deal with his weight. In time he was brought back (despite not shedding the pounds) and pushed again. Then he slipped and so the pattern has continued. He can be off TV for weeks at a time then come in and be put in a upper mid-card program. I'd give him a "7."

potential - This is another what that is greatly opinion and I can only go on what I see, others' think, and so on. Think of this as a percentage rating, if a guy has a 7, it means he's at about 30% of his potential right now and room for improve seems definate and he could definately make great strides. Older guys are looked at by what they can do to give back as opposed to younger guys. Some semi-actives like Flair, Hogan, Savage, etc. could do a lot to put over up-and-comers, though their in-ring potential is probably in the negatives.
example - Red, one of the most exciting indy stars today. Still young and new to wrestling, Red has dazzled many with uncanny athleticism. Though he comes across as a spot machine, Red is learned and continues to improve. If put through some camps or dojos and given some constant work, Red could develop into one of the best American flyers yet. He does need the work though, which is not a negative, it means the potential is definitely there, but needs more coaxing. I'd give him an "8."