To become a elder, a male first becomes a ministerial servant. To do that, you have to kiss the elders' asses and do whatever is asked of you- handle chores at the Kingdom Hall, take the elderly to and from the meetings, and highlight all the answers to questions in your study materials.
Beyond that, to work toward being an elder, you have to get plenty of recruiting time in every month, not have any incidents of being too drunk or going to R-rated movies or getting into any trouble of any kind, be very careful about how you talk to women whether you are married or not. One extremely important thing is for you to be able to spew out doctrines from the platform in various talk assignments.
If you are the son of an elder and are squeaky clean, you can make elder faster. If you directly kiss ass to the Circuit overseer and donate money to him (the green handshake), you can make elder faster. (I wish I was kidding.) In many cases, if you do all kinds of ass-kissing to the local elders and act like you don't really think you are qualified to be an elder, you will typically make elder faster.
Even when I was an elder, I told people not to tell the elders everything, not to confess to everything you do that is against JW rules. Now, I would say it stronger. Say nothing much about anything personal or beliefs to them. Learn to say "I am fine. No, I will call you if I need you."