Obviously I try to create an environment of encouragement and frequent verbal praise. However, I've found that adding a bit extra can really make the difference in getting students to go the extra mile.
In previous years, I've tried a few different things.
1. I've tried classroom incentives of earning letters to "free time" on the board. When a class earned all 8 letters, they got 15 minutes to chat at the end of class on Friday. What I liked about this system was that I could start the semester with very frequent rewards to clearly show students what behaviors I liked, and the type of work ethic that would earn them more letters. Over the course of the semester, they had to work harder and harder and be increasingly on task to earn letters. However, this system didn't give me a way to praise individual students, and the incentive of chat time really wasn't enough. Most students would just use the time to finish up some homework for another class.
2. I've also tried a ticket system. I gave tickets to individual students or small groups (to split up) for various on task behaviors, catching mistakes, being encouraging or helpful, and working on the board in front of the class. A few times I also gave these out for really great questions or comments during discussions. Students could redeem tickets for extra restroom passes, homework passes, extra credit, or mechanical pencils. I liked the versatility of this system, but not the time I had to spend cutting them out. Also, I felt like students didn't have an easy way to keep up with them. (You know how the inside of a 9th grade backpack looks like - picture plenty of these getting lost in that abyss.)
3. Last year, I tried a similar system to the tickets, but instead I created a point system. I kept physical tickets for some things (students coming up to the board or spontaneous reasons), but students also could earn tickets from good test and quiz grades. I gave 3 tickets for an A, 2 for a B, and 1 for a C. Students had to keep up with their grades and ticket totals in a chart in their interactive notebooks.
This system was very similar to the previous one, but most students only kept track of physical tickets, and didn't use the chart. This system was also very difficult for me to verify rewards - I was pretty much trusting that they had the points they had written on the chart. Very rarely did I "audit" a chart to check their grades as well - it simply took too much time.
This year, I just want something SIMPLE. I've learned whatever system I use needs to be easy to verify (or hard to fake), have a physical component, and needs to have incentives worth working toward. I settled on punch cards. (Yes, like the type you get at Sweet Frog or Bealls Outlet) Students will have a list of what gets them a punch or stamp (I haven't decided which to use). They have a list of 3 incentives to choose from. When the card is full, it either becomes a homework pass, or 5 points on a test or their notebook grade. I've decided to give one punch for each 100% on homework (work shown, neat, and complete). They can also get a punch for an A on a test, or for passing a color level on their differentiated assignments (more on that later). They'll get a business card-sized punch card made of heavy duty cardstock, and it's their job to keep up with it. I bought 2 special hole punches that punch shapes (a star and a heart), and I also have self-inking stamps. I'm hoping that none of my students will have a star shaped hole punch at home, but I guess we'll see.
If you would like to download my punch pass, visit my TPT store at tinyurl.com/learningwithtapeTPT