The fundamentals of passing accuracy and weight, coupled with clever movement don’t change whether you’re coaching an 8, 10, 12 or 14 year old. What does change is the manner in which you deliver the information – perhaps in smaller chunks for younger players. 

I’d also expect U13s to be zipping in passes at a much greater pace than U10 and I’d expect my players to be able to handle the extra speed and still control the ball.

The second question is really interesting and my coaching style depends heavily on building a rapport with my players, knowing their names and relating the practice to their interests. In an early session I will take more time to discover these bits of information and make sure the session is really good fun before I risk getting heavy with technical information.

One of the World’s best at building instant rapport with players is Tosh Farrell (who coached Rooney and Rodwell amongst many others). I interviewed him for this site and it’s worth a listen for some great tips about age-appropriate coaching.

You can find it here : http://betterfootball.net/soccer-coaching/player-friendly-development-tosh-farrell/

I have another Question: What is the difference between coaching the session to under 10
and under 13? 

also 

What the difference coaching session to New group of players and the one you have done previously?

In the Barcelona mantra “offer” means get into space or a position to receive the ball and progress the attack, and then call or indicate (with hands, eye contact, bodyshape) that you want the ball back.

When an entire team shares this mentality the passer always has multiple options and even the toughest defences can be pulled around the pitch and opened up.