The seven principles of offense and defense written below were created by Del Harris. I think they could be very useful in the creation and evaluation of your system of play.
Principles of Offense
1. Penetration of the Defense
3. Ball and Player Movement
4. Options for Ball Handler
5. Offensive Rebound and Defensive Balance
6. To Fill Any Spot
7. Utilize Individual Talents
Principles of Defense
1. Have a great transition from offense to defense.
2. Push the ball to a sideline in order to establish a good weakside defense as early as possible.
3. Keep the ball from reversing easily from side to side.
4. Concentrate on stopping penetration via dribble and pass.
5. Prevent a consistent low post attack.
6. Rotate to assist a teammate.
7. Rebound and pick up loose balls.