I'm sure they'll discover more as Marzano now has a reseach lab in conjunction with Solution Tree.

     Know this: every one of the basic nine work, but you must be consistent and follow through. 

Here they are:

Researchers at Mid-continent Research for Education and Learning (McREL) have identified nine instructional strategies that are most likely to improve student achievement across all content areas and across all grade levels. These strategies are explained in the book Classroom Instruction That Works by Robert Marzano, Debra Pickering, and Jane Pollock.

1. Identifying similarities and differences
2. Summarizing and note taking
3. Reinforcing effort and providing recognition
4. Homework and practice
5. Nonlinguistic representations
6. Cooperative learning
7. Setting objectives and providing feedback
8. Generating and testing hypotheses
9. Cues, questions, and advance organizers

     The catch is, you must implement the strategies.  Try adding one at a time to your repertoire. For example: that weekly vocab or math quiz you give every Friday. This is only helpful for feedback and reinforcement if you go over the words students missed the next day.  Don't just hand back tests with wrong answers slashed.  If kids don't get where they went wrong and the right answer, they'll repeat the error next time. 

   That's the whole point of formative tests. Change your lesson plans! Say it another way.  Incorporate group learning.  Have a kid play teacher of the day, complete with access to the white board. Use an advanced organizer. Do it differently. Provide levels of entry so that your GT students, ESL and spec ed students can all jump into knowledge somewhere.