For profoundly gifted students, the best learning environment is an advanced curriculum in a self-contained classroom with intellectual peers. For gifted students in a regular classroom, a focus on individual strengths and flexible strategies, such as the ones outlined in Successful Strategies for Teaching Gifted Learners, will help.
For ideas about what your school can do, please read Twelve Cost Effective Educational Options for Serving Gifted Students. Also, these books offer practical ideas for teachers: