For a multi-sprint sport such as football absolute speed is not the most important factor. Speed off the mark, acceleration and agility are.
Instructions
1. Warm up thoroughly. Speed and agility drills may not leave you out of breath but they do put considerable strain on your body
2. Speed and agility drills should be performed either on separate days to other training or at the start of a training session after the warm up.
3. You will gain most benefit from these speed and agility drills if you have previously developed a solid strength and power base.
4. A typical session may consist of approximately 5 sets of 10 repetitions (each sprint being 1 repetition). Work to rest ratio should be 1:5 i.e. a 5 second sprint should be followed by a 25 second recovery period.
5.Choose 2 or 3 of the speed and agility drills below to make up the session, keeping to the recommended number of sets and repetitions.
6.To really benifit from this you will have to do this 3-5 times a week, it takes some commitment.
Speed And Agility Drills
1. Basic Sprints
Set 2 cones out 10-20 metres apart. Sprint from one cone to the next and slowly jog back to the start. Simple enough
2. Rolling Start
Exactly the same as above except you jog for 10 metres before sprinting. This drill is specifically designed to enhance acceleration rather than speed off the mark. Try running backwards or side stepping aswell just to mix it up.
3. Up Hill Sprints
In competition the first few strides are crucial. Running up a slight hill (about 30 degrees) helps to develop power and acceleration. Keep the distances short (10-15 metres) and allow extra rest between sets and reps as it is much more demanding.
4. Down Hill Sprints (Over speed training)
Down hill speed and agility drills help to develop leg speed and co-ordination. This is sometimes referred to as over-speed training. Keep the distance short (10-15 metres) and make sure the hill is only slight or you'll end up doing a Klinsmann http://www.youtube.com/watch?v=t8Bx8Jc2HrQ
5. Hollow Sprints
Set 5 cones out in 30 metres intervals. Sprint 30 metres, jog 30 metres, sprint 30 metres and jog 30 metres to the final cone. Walk back to the start and repeat.
6. Cruise And Sprint
Mark out a distance of 100 metres(or use a track if it is available) From the start gradually accelerate to reach full speed at about 60 metres. Sprint all out for the final 40 metres.
Reduce the number of repetitions for this exercise as it takes longer to complete.
7. The Snake
Set up a series of 6-8 cones in a straight line about 1 metre apart. Weave in and out of the cones, turn and weave back to the start.
8. Follow The Leader
A training partner and large area is required for this drill.(half a football pitch or the inside of the 18yard box for tighter turns) Have your training partner jog, run and sprint randomly over the area. You must try to shadow them as closely as possible. This is an excellent drill that helps to develop reaction time, agility, acceleration and speed endurance. (depending how fit your partner is

Why not give it a go?