Have a plan and explain it
If possible start the exhibition or event with clear explanation of the adaptations to the venue which will make life easier. If that isn't possible, the marketing information distributed prior to the event provides a really good space to explain things. Remember that dyslexia can make reading instructions difficult so the information needs to be accessible to everyone.
Quiet spaces are a good idea
A quiet space is necessary for not only neurodiverse attendees, but anyone who wants to get away from the noise and the bustle of your dynamic event. Event organisers are more aware that people need a rest from things occasionally. If that means a space with comfy chairs, relaxing music and refreshments, then exhibitions and events can provide that. I have heard of one event where silence was necessary for the whole week. One delegate couldn't handle that and left saying that they were leaving because they couldn't handle the silence. It works both ways.
Bathroom spaces can be tricky
Bathroom facilities can cause problems for both disabled and gender diverse participants. Unseen or visible disability can cause problems in using traditional bathroom provision and the event organiser needs to have a look at the venue's offer and make plans to accommodate everyone's needs.
Staff training is essential
Staff need to be trained to be aware that some attendees may need more attention than others and should be aware of anyone who seems not to be coping. On the otherhand, some attendees may feel aggressive or intimidated by attendees that they see as 'other' and the staff need to be able to tactfully difuse situations as they arise. Although I've very rarely seen this happen at events, it's best to make the staff aware of what they need to do.
Tech can help communication
Use tech to help people communicate if they are shy or English isn't their first language. Tech can be used in other ways to guide attendees around the event, record their experiences and feedback their thoughts - invaluable for organising the next event!
Have you thought about access to and from the venue
Transport is an area that's often forgotten because it doesn't come under the event organiser's budget but if you can't get everyone to your event either because the train station doesn't have a lift to get from one platform to another or there's no disabled parking or it's an awkward journey which makes life difficult for people with caring duties, try another, more suitable venue. Is your event accessible for SMEs with little money to attend events or exhibitions? Making sure that the travel cost isn't exhorbitant will give an extra incentive to attend.
A carefully thought out agenda is worthwhile
The agenda needs to take into account the cost of travelling, can you start when the travel cost is reduced? Does it need to be a 2 day event with the associated hotel costs or can you condense it into 1 day instead? Look for times when breaks can be inserted into the agenda so that neurodiverse attendees can be peaceful for a while. Have you made enough time for disabled attendees to use the bathroom and have refreshments as well? Circulating an agenda prior to the event helps people plan their day more effectively and helps them to get the most out of your efforts.
A few other helpful tips:
Make sure the refreshments are at a suitable height for able bodied and disabled people to access them.
If your audience is likely to include parents of young children, can you offer childcare facilities or could you welcome the children to your event? Not all events are suitable for children, so perhaps other arrangements could be made. Ikea have a wonderful creche facility as they've realised that parents will spend more time and money if their small children are not involved in the shopping experience!
Pride badges worn by the staff (who are happy to wear them of course) can be seen as welcoming to the LGBTQ+ community.
Subtitles on keynote speakers' presentations or tech that can translate speech into text is essential for attendees with hearing problems.