If you need support organizing practices, here a few free websites with drills for all ages:
Coaches Manual – Lessons
US_Youth_Soccer_Lessons
NSCAA_Soccer_Fundamentals

A good source for advanced soccer drills, some are free:
Fifa drills for kids
UEFA Drills
Worldclass coaching
Free Ebooks
Soccer-Coaches-Drills

Inexpensive iOS applications 99 skills
Coerver Soccer Drills for Individual moves
NSCAA Drills

Coaching Books:
Applied Sport Psychology
Successful COACHING
Formations:4-2-3-1

US Youth Soccer video coaching:
Drills

Preventing common Injury: Knee… from US Soccer 
Hollister Tremors_Player_development Priorities_