• Enhanced fitness
• Enhanced ability to perform skilled movements
• Increased mental and physical relaxation
• Reduced risk of injury to joints, muscles and tendons
• Reduced muscle soreness
• Reduced muscle tension
• Improvements in the connective tissue

It is very important to warm up before stretching.  Stretching a cold muscle is a terrible idea.  I generally do my stretching either after a cardio session or after doing some foam rolling (which warms up the muscle via massage).  Warming up can include joint rotations.  There is also a recommended order for doing your stretching.  You should stretch in the following order:

• Back
• sides
• neck
• forearm and wrists
• triceps
• chest
• buttocks
• groin
• thighs
• calves
• shins
• hamstrings
• instep

This is designed to cover your entire body.  You should hold each stretch 15 to 20 seconds.  Maintain normal breathing patterns.   Always stretch after doing foam rolling as it helps to improve functionality of both the muscle and the joint and make the changes more permanent.

If you want a detailed plan for stretching along with diagrams that show you how to do the stretches, I recommend the book Stretching by Bob Anderson.