Don't consider stretching a warm-up. You can hurt yourself if you stretch cold muscles.
Focus on major muscle groups. This keeps things consistent.
Don't bounce. Bouncing as you stretch can cause small tears in the muscle.
Don't aim for pain. If it hurts, you've pushed too far.
Make stretches sport specific. Some evidence suggests that it's helpful to do stretches tailored for your sport or activity.
Keep up with your stretching. If you don't stretch regularly, you risk losing any benefits that stretching offered.
Bring movement into your stretching. Gentle movement can help you be more flexible in specific movements.