I use what can best be discribed as a behavior modification technique. It has 3 components, and sounds complicated, but it works for my 8th grade students. It (or some variation) might work for you.
1. Students have the opportunity to earn 7 points per day, 35 per week. They are rewarded if they earn 15 with free choice seating, chocolate, a few points on a test, etc. depending on the total points earned. They earn points for behavior I want to encourage ie. arriving on time, getting straight to work on their journals, being respectful, not shouting out answers... you get the idea.
2. Mistake points. This is a student favorite. Every time I make a mistake, if a student catches it and proves me wrong--for example I spell peninsula like this "penninsula" I put a mistake point in their classes column. They have to PROVE that the word is wrong,by using a dictionary, or other source. The mistake needs to be one that effects their learning (in other words verbal diarrhea doesn't count, but a mistatement of fact does). The students have to be the one to catch it, if I self correct, BEFORE they catch it, it doesn't count. When they accumulate(SP?) 5 mistakes, the whole class gets a small piece of chocolate. They like the chocolate & the fact that I am willing to admit to mistakes.
3. Strikes. When students are being unruly, and have already lost their point in # 1 for not calling out or whatever, I give them strikes. For every three strikes, they loose a mistake point.
This might not work for everybody, but it has been effective for me! Is this your first year? If it is, you will need to do a fair amount of experimenting. Don't be afraid to chuck everything and start over! Use humor, treat your students with dignity and respect, keep them busy, and try to meet them where they are. Keep your expectations high, they WILL rise to them. Don't get discouraged, try to find a mentor.