You did a very good job Jeff. As general feedback I recommend you talk less. Eliminate filler phrases like "there you go" and the rep counting. Saying something like "good" is ok if it lets the client know they specifically executed something that you were working on. If you are using "good" as a filler I would drop that too.
For specific feedback on squat I would have cued hip drive more. For bench I would have given an action cue instead to push the bar toward his spot on the ceiling or towards the rack and not of a "don't do this" cue. For deadlift I would have cued knees out in the setup, to give them an opportunity to set their low back better. Also, do not let him drop his butt. You can say things like "hips high" or "shoulders in front of the bar" or use a tactile cue to draw attention to the dropping.
If you want regular feedback on your coaching you should check out the coaches' prep course. This is a built-in part of the process to progress through the course.
Starting Strength Coach Prep Course – The Aasgaard Company
Hope this helps!