Do you want to get faster or quicker? They can require different training techniques. As a college-level athlete who played basketball and ran track (long jumper and hurdler), I trained differently to build top-end speed and explosiveness for track as opposed to quickness for basketball.
Top end speed requires explosive training of the fast twitch muscle fibers and can involve putting on muscle. This helps with quickness as well, but too much can add bulk. Polymetrics, resistance sprinting using a slight grade or parachute, low rep, high weight training (squats, clean, etc) and the like will build speed. Just look at how muscular sprinters are.
Agility ladders, polymetrics, court drills, running steps and the like helped build quickness. Some weight traning as well, but you don't want to get as bulky for quickness. Basketball players and tennis players tend to be leaner and quick.
Having switched from basketball to tennis, quickness and lateral movement seem to be more important than all-out top-end speed.