Speed is a difference maker in every sport, from linear speed to the ability to accelerate, decelerate and change direction quickly. Arguably, the biggest contributors to success in sports are quickness and agility. As an offensive player, they are important for creating scoring opportunities; on defense, you need them to effectively guard your opponent.  (See The Art of Deception in Basketball.)
The best ways to develop quickness and agility are as follows:

Strengthen Your Legs

Speed and agility don’t really exist outside the context of lower-extremity strength and power; they’re a direct result of the amount of ground force an athlete can generate. It’s a simple concept: stronger legs generate more force against the ground. 

• Deadlifts
• Squats (learn how to perform basic squats and major variations at STACK’s Squat page)
• Explosive exercises like plyometrics (Train Smarter With Dos and Don’ts of Plyometrics)

Perform Quickness Drills

The great thing about quickness drills is that they are limited only by your imagination. Incorporate variations that reflect the demands of your sport for acceleration, deceleration, change of direction and reaction.

• Cone drills: 4-Cone (Box) Drill; 3-Cone (“L”) Drill Combine Testing: Pro-Agility Shuttle
• Agility ladder drills
• Reflective drills: where you have to “mimic” the movement patterns of a partner (think guarding him or her), for a pre-determined period of time.