Good question. For me, working with an age range from about 4 to 9, our emphasis is almost exclusively on being in possession, i.e. individually keeping the ball close. Then during certain exercises, kids will simply lose possession because they cannot keep close control and/or shield the ball. So you don't actually need to coach any type of tackling, it just happens naturally with minimal contact.
It is more of an issue among the older players. I have noted some kids who are completely fearless when it comes to putting their foot in, and they are also the ones most likely to commit a foul simply because they cannot properly judge the action, while others don't like any form of contact.
For me, the solution would be to encourage the kids to 'press' more, i.e. shut the player down, block him off, rather than 'tackle'. This can be worked on in small sided games, or 2 v 2s, 3 v 3s, etc. But it is quite tricky to put into practice at this age (especially with only 1 hour each week) which is the other reason for focusing on being in possession.
concentrate on the technique of delaying, diverting and bodyshape.
being able to recognise a mistake and "pounce" on it.
this will hopefully cancel out being square on to a player making it easier to passed, will also the limit of full blown contact where injury or fouls are a higher percentage
For me its the four D's for the younger age groups:-
Delay - Can we get behind the ball carrier and slow them down to allow for support to get back?
Deny - Can we deny the opposition space in which to think and move the ball on?
Deflect - Can we force the opposition backward (which is the success element) or can we shepherd them into an area away from our goal?
Disrupt - Can we win the ball and turn the situation into a counter attack to our advantage?
How do we do the above?
Principally, body shape, having the defender with an open body shape, knees bent and 'showing' the attacker away from the goal perhaps toward the wings of the pitch. You can do a lot of work here about what parts of the pitch might be considered 'safe' and what might be considered a 'danger' but depends on the age and stage of your kids.
Triggers - At what point do we change from delay to deny, or to disrupt? Getting the players to understand when to step in and steal the ball, for example do the opposition have a bad touch? is the pass in to the opposition overhit such that you can step in straight away? Do they miscontrol? - All those are triggers to steal.
In terms of how we coach this in an unopposed level, *** Bate was a master at coaching kids with these sorts of principles. This link to one of his sessions is a bit old but i return to it quite often to get back to basics. https://www.youtube.com/watch?v=8oQ0c8sS58M&t=1833s This would work well even with quite young kids i think.
