1. Change the entry requirements for eduction courses at uni. Undergrad - High School leavers must get a minimum B+ for English and B for Maths B or A for Maths A. Postgrad - Minimum GPA of 5. Actually, don't accept anyone straight from school. We want teachers who have a thirst to learn - not people who are thirsty for qualification. Let them get a BA or BSc or something first.
2. For Professional Development, encourage teachers to do further study in anything they are interested in. If teachers are excited about learning themselves they will teach better.
3. Have educationalists start talking to psychologists. There is a whole lot of research out there about how kids learn that teachers never ever read.
4. Employ many more guidance officers (school based psychologists). They can do a swag of assessments on kids to help work out why they are having troubles with stuff. What usually happens is that if a kid can't read (or something) they are put on a particular program that the school has decided to use without asking whether or not it is appropriate for that child. You need to diagnose what is going wrong before you can fix the problem. GO's can help with that. (This one would be very expensive.)
5. Give teachers freedom to teach in the way they think is best for the kids. Specify outcomes not the method.