Seeing nobody else has replied, I'll have a go.
I'm coaching an U-16 team, but we have kids as young as 8. As a group, I talk, they listen. We have discussion at a one one one level, but when addressing the group I want to keep it brief.
Evaluation at a game is pretty much how I see our performance on the day. I'll talk to kids 1 on 1 about their batting when they get out (or retire). At the break of innings I'll make some comments for a couple minutes on how we've gone, what worked, what we need to work on, and what to focus on in the next innings. They get a similar two minute debrief after the game. Constructive criticism is fine, but I always try to end any chat with a positive point, and award the game ball to someone who did something special.
When I get home I write up the scores in a spreadsheet. It started off as a way of keeping track of who was given the ball, and how many games kids had played, as we have some spares that I have to rotate, but it ended up getting quite in depth!
I don't individually review and rate each player, but enter everyone's batting, bowling and fielding figures so that I can easily keep an eye on their performance as the year goes on.
As I'm entering that info every week, I find myself looking back at the weeks before and comparing. The spreadsheet makes this a lot easier than flicking through the pages of a scorebook.
As well as the stats, I write down a quick review of the game, and comment on what stood out - good or bad, and areas we need to work on to improve. Most of the time it's not batting or bowling as we work on that every week, but things like field placement, tactics to oposition players, running between wickets, reading the game situation and batting accordingly etc etc.
Come training night there's another 3 minute recap of the game and what we need to work on, and I'll have some exercises to target that, as well as the usual net work.
The kids have been at school all day, and the last thing they want is to listen to the coach rave on, so I try to keep the chat as brief as possible.