Elders
Elders are the overseers of the church ultimately responsible for the spiritual well-being of each member. The Bible defines the characteristics of an elder in Titus 1: 6-9 (NIV):

⁶An elder must be blameless, the husband of but one wife, a man whose children believe and are not open to the charge of being wild and disobedient. ⁷Since an overseer is entrusted with God’s work, he must be blameless – not overbearing, not quick-tempered, not given to drunkenness, not violent, not pursuing dishonest gain.⁸Rather he must be hospitable, one who loves what is good, who is self-controlled, upright, holy and disciplined.⁹He must hold firmly to the trustworthy message as it has been taught, so that he can encourage others by sound doctrine and refute those who oppose it.

Deacons
The word deacon means “one who serves. The Bible defines the characteristics of a deacon in I Timothy 3: 8-10, 12 (NIV):

⁸Deacons … are to be men worthy of respect, sincere, not indulging in much wine, and not pursuing dishonest gain.⁹They must keep hold of the deep truths of the faith with a clear conscience. ¹⁰They must first be tested; and then if there is nothing against them, let them serve as deacons.

¹²A deacon must be the husband of but one wife and must manage his children and his household well.

Ministers
Ministers are charged with preaching the word of God and evangelizing His people. The Bible addresses this in 2 Timothy 4: 2-5 (NIV):

²Preach the Good News.  Be ready at all times, and tell people what they need to do.  Tell them when they are wrong.  Encourage them with great patience and careful teaching, ³because the time will come when people will not listen to the true teaching but will find many more teachers who please them by saying the things they want to hear.  ⁴They will stop listening to the truth and will begin to follow false stores.  But you should control yourself at all times, accept troubles, do the work of telling the Good News, and complete all the duties of a servant of God.