The best advice when going to the theatre

In exactly 3 weeks time ​I'm going to London for the day to have a look around. And also getting the chance to see magic show Now You See Me Live at the London Coliseum (2:30pm show) ​which whilst I'm extremely excited because I absolutely love magic/illusion. And it also includes 3 magicians who were on Britain's Got Talent which is just so cool.

​But I also find theaters a bit tricky. Especially as someone who has Autism & ADHD. As I often find the whole atmosphere extremely overwhelming. And while it's a show designed for all ages which is awesome. I really want to go there with a positive mindset and just enjoy the show. And I was wondering if anyone here could give me the best advice to when I go and see this show in a couple of weeks so I really enjoy it the day I go.