Ultimately, the best players and coaches are in an environment that fosters thinking. Tactics are thinking, and the game without thinking is no game at all. Do yourself and your players a favor, and begin to develop players who are technically competent and comfortable thinking for themselves.

I learnt very early on the value of unopposed practice- followed by interference eg. 7 vs 2  . Followed by a small side game as a session .
 FA Youth module 2 /level 2 & the  Coerver youth diploma all enforced this,  as a perfect coaching session . Great piece below on tactics and giving players ownership of the session, my personal choice is conditioned games (the rules of the game dictate how they play) ie midfield rotation/ playing out from the back / wing play / switching play  .There are endless games out there and most are free online. Great blog below for the interested :)  
















http://thecoachingjourney.org/2015/08/23/no-tactics-until-13-nonsense/