Strengthen your core every day. Exercises like planks, side planks and bridges can be done every day. A strong core is important for speed endurance.
How much lower body strength do you need to develop optimum power and speed? A male should be able to squat his body weight 8-10 times and a female should be able to squat about 75% of her body weight 8-10 times. If you are not able to squat, then you should be able to leg press about 1.5 times your body weight 8-10 times.
It doesn't help you to continually get stronger if power development is not there also. Power, or speed strength (how fast your muscles can produce force) is one of the best physical predictors of success in sports.
Many times, its practicing the "little things" that make you better!