Soccer is a game that focuses on running speed, stamina and of course technique, i.e. controlling the ball. Apart from tactics, team play, group motivation, these are the individual parts that let you stick out from other players. The best players in the world all have excellent technique and speed.

To improve my technique with the ball I categorized what the important parts were for me.
I. Passing
II. Dribbling
III. Shooting

To improve speed there are two basic distinctions.
I. Acceleration
II. Maximal Speed

Spend at least one hour each day practicing, the more time you have, the better.

Day 1: Running - Acceleration.
Do lots of uphill runs, small steps no long distances.

Day 2: Tech. - Passing.
If you cant find someone to practice with, use a wall and let the ball bounce back after shooting from a distance. Start with one meter and vary the distance (20 cm - 10 m) This will also improve your trapping abilities.

Day 3: Tech. - Dribbling.
Try to always keep the ball close to your feet. Turn around and sprint. Practice a few tricks. (e.g. google for "Cruyff turn")

Day 4: Running - Max Speed.
Go for downhill runs, but don't fall.

Day 5: Tech. - Shooting.
Find a target and shoot a ball from 20 meters. Try to hit better than the last shot. Try different methods with ball lying still or rolling.

Day 6: Running - Stamina
Do slower runs where your heart-rate does not exceed 140bpm. Aim for 90 minute-runs.

Day 7: Off