One of the horses at the barn I train, has an issue with stopping. As soon as someone gets on him she refuses to stop and starts to walk. She got checked by a vet and she's alright. Do you know why ?
He probably doesn't have any experience saddle work and if he did it might have been a negative experience, I would work in hand work then do undersaddle let work to let him know it's ok.
What are your tips for selling a horse to an amateur rider (videos, ads...)?
Just pictures and videos of the horse doing whatever discipline u do and are selling ur horse for. If u do flat than just put videos of ur horse doing flat. If u do jumping then video their flat and their jumping if u do eventing the show flat, jumping, and xc in a video. Plus the pictures of the horse. Then I would do a brief description of who u want to buy the horse and what the horse has done and can do.