1. Get it in writing. Get a contract, job description. Know what is expected of you.
2. Get your office organized. The more organized chaos you have the better you have for administrative and relationship building.
3. Get to know your leaders. Know their giftedness, take them to lunch. Spend time together building a team. The more you support the Church Staff and stand united - the better.
4. Get to know the parents. Know what their expectations are. Get feedback on what they want for their child. Spend time building relationships with the parents (Moreso than even the teens)
5. Build your team. Get to know the sponsors. Slowly build your team. Get to what what they have do in the past, and what you are planning for the future.
6. Get to know your students. Especially your student leaders. Mentor, disciple, impact, have a plan and a purpose for every activity and lesson you do.
7. Don't change a Thing. At least not yet. Evaluate. Spend the first couple of months - maybe not even teaching but observing, look at the overall - what works, what doesn't. Be prepared to get your Senior pastor on board when you have to REVAMP, and possibly fire or rather re-assign other volunteers to other ministries. You are in charge - but that takes time to make the program Yours (After much consideration and prayer of course of where God would have you)
8. Have a network. Have some mentors, a network of youthworkers to rant, to bounce things off of, as well as some accountability. Build long lasting friendships outside even the congregation you are serving. Be Kingdom Building, not always Congregational. (There is a difference).
9. Build your resources. Have a library. Learn. Goto Conventions. Adapt, steal, borrow, use what might fit in your context of youth ministry.
10. Take Time for your own Spiritual Journey. Make sure you are feeding your soul. Don't get burnout. Be encouraged.
Other Resources That you might Find helpful:
Your First two Years in Youth Ministry by Doug Fields.
Starting Right - thinking theological about Youth Ministry - Dean, Clark & Rahn.
The Top 12 Resources Youth Workers Want - Jonathon R. McKee
10 Things I wished I had known when I started Youth Ministry - Revellyn Pletcher