Create a practice session plan in advance and have as much of the field prepared for play as possible.
Players need and like, a basic routine and should know what to do when they arrive, when the water breaks are etc. The content and focus will change but you will save a lot of time if you do not have to constantly stop to educate the group on what is next and answer practice structure questions. Practices should have a pre-practice routine while players gather, warm-up, ball control skills session, match related activity, then scrimmage (let them play).
Select one soccer skill or area to improve upon for each practice. This may involve a related skill as progression. Less is more!
Fine tune and perfect only the skills that are developmentally obtainable at the age by adding pressure (time & space). Emphasize quality over quantity in terms skill drills.
Create practices that logically progress from one activity to another (within the practice objective) while positively challenging all players. Use repetition as means to reinforce technique. Repetition is key to any training, but vary the content and challenge to keep interest & performance level high.
Maximize time with the ball and keep all players involved in some way as much as possible (Note: Every player should have a ball).
Keep it simple, demonstrate to provide a good visual reference (utilize older player assistants or good demonstrators from your own team if needed).
At all ages challenge players with soccer related games or challenges for nearly every soccer activity.
Fitness training should be accomplished as part of the soccer activities. Older age groups, U12 and higher, may need to supplement with additional fitness activities.
Create an atmosphere where positive attitude, teamwork and sportsmanship are reinforced in every aspect of your coaching. (Let all players have a chance to lead or demonstrate some aspect of the practice) Remember to encourage more and criticize less. Find the positive!