1. Don't be afraid to ask the search committee hard questions. This is a rookie error. When you're young, you just want a job. But this is not like applying at McDonald's or Target. The goal is NOT to get through the interview as quickly as possible. In fact, if both sides are doing their due diligence, this process will take several months. Don't be afraid to ask very direct questions. You want to go into this position as well-informed as possible. (Side note: I personally think one of the LAST questions that should be dealt with is salary. Seek God's direction before you seek your checkbook's direction.)
2. Dial down beyond philosophy to implementation. What I mean by this is every church is going to say "we want to grow" or "we want to see change" or "we want someone young to help us reach our community". If you're not careful, you'll get so excited about these statements that you'll start thinking, "Great! We're on the same page." This is a huge mistake! Take it a few steps further and start asking "Are you willing to do ____________, to see the church grow?" or "What kind of things would you NOT want to see change in your church?" Many smaller, established churches will talk a big game about change and growth, but what they really mean is, "We want you to attract new families to our church, but don't change our building, our music, our structure, or our priorities." Dial down hard on this. Get detailed. Ask if, in the interest of church growth, they'd be willing to change their style of music, their service times, the church decor, the church location or name, kill some ineffective programs and start some new ones, be comfortable with really reaching out to "the least of these", etc... Not that you plan on changing ALL of that, but how far are they willing to go?
3. Find out if the leadership and the congregation are on the same page. This is extremely important if you're interviewing for a staff position. The pastor might be a great man with a great vision, but it's good to find out if the church shares his vision. This might not change your decision, but at least you'll be better prepared for potential battles.
4. Be yourself in the interview process. Don't put on your best face or, worse, a fake one. Just share your heart. Share what kind of ministry really gets you excited -- even if it's weird. It's in everyone's best interest if the church knows exactly what they're getting when they hire you. If you're not a coat and tie kind of guy, then don't wear one in the interview. Present yourself in the interview or sermon you give the same way you want to work/minister if you get the position.
5. Don't settle because you're trying to leave a bad situation. If you're currently in a dead-end church or miserable in your current position, don't settle for a less-than-ideal church just to quickly get out of the less-than-ideal church you're currently in. Be patient. God's timing is perfect. If he hasn't moved you on to a different ministry, it's because he still has something for you to learn in the current one.
6. "God's will" is not a Get-Out-of-Jail-Free card. People will want to know why you're leaving them. Rookies always say the same thing -- "I really felt it was God's will to move on." If that is not definitively true, then don't say it. You're confusing everyone. You also told those same people that you felt it was God's will to be their pastor or youth pastor or whatever. If we're not careful, we make God look indecisive. Reserve the "God's will" label for those decisions that you REALLY, genuinely feel like were His will. I've said before, I've only had two decisions in my life that I knew were God's will -- answering the call to preach at age 16 and accepting the call to be Living Hope's pastor two years ago. That's it. Every other decision was made out of convenience, fear, because it made sense for our family, exploration, emotion, etc... Be honest about why you're leaving, but don't be hurtful. It's always a bad idea to burn your bridges. Leave gracefully.