JW-Watchtower Theory: A man is living a Christian life, taking the lead, setting a fine example, a good well rounded family man, who is mature, loving, balanced, and caring. His peers look to him for guidance. The JW Elders see his example, and determine that "holy spirit" has already started using the man as an Elder, and recommend him for appointment as a recognition of what the 'hs' has already done. The CO also sees and accepts this, and mails his recommendation from the Elders off to the Society. There, after much prayer and consideration, the Committee who reviews these CO recommendations determines that a man recommended is truly living the Christian life, and accepts the recommendation, and approves the appointment "Already made" by holy spirit.
JW Reality: A man shows up at meetings, learns how to comment by parroting words from Watchtower books, gets out door to door at least 12 to 15 hours a month, and Aux. Pioneer at least once a year, volunteers to clean toilets and cut grass at the Kingdom Hall, and do any other odd jobs requested. Make friends with the Elders, and constantly find some reason to be in contact with them, being noticed cleaning toilets and cutting grass ... like getting the PO's approval for the best toilet cleaner, or asking where to put grass clippings ... this constant exposure, field service, meeting attendance, commenting, volunteering is what influences Elders more than anything else. Oh, and if a man is in a congregation where some of the Elders have a few brains ... then he must not say stupid things or act like a nerd.
Actual Appointment: When the Elders are ready after some mysterious 'holding period' needed to 'observe' a man, a time frame unknown to any human, they meet, and discusses appointments. "Hey, Harry, whad ya think of George as an Elder?" ... "Well, Sam, he is at meetings regularly, and comments well ... yep, George has my vote." After this type of 'recognition of what the 'holy spirit' has done, they parade the man in front of the CO with parts in the TMS and Service Meeting to be sure the CO knows their pick. The CO of course arranges to work in Field Service with the prospective Elder. The CO completes a recommendation form in his meeting with Elders ... usually there is little discussion, except for discussing how much they like George.
The form states the baptism date, age, birthday, Anointed or OS, and a short statement by the CO promoting the prospective Elder.
The Society: I understand that they have Committees that handle the recommendations for appointment and removal of Elders, MS, Pioneers, etc. I have no clue as to how they process these recommendations ... but I imagine that they check the Watchtower files to make sure that the prospective Elder does not have any DF/DA record unknown to the Elders and CO ... and they make sure the form is filled out correctly, and that the prospective Elder is not too young, or if claiming to be anointed that he has been a JW for a good period of time. They place a "Green Check" mark by the approved names, and "red-line" the unapproved names, and mail it back to the congregation ... and that's about it.