The first lesson I learnt was that exhibiting a model railway layout was very hard work. The second lesson was that it was also very rewarding.
The viewing public are usually interested in and appreciative of what they see. I have had many conversations with spectators ranging from "How do you arrange your loco springing?" to "In real life you would be sacked for doing that!" after I ran a loco into the turntable pit.
So what would I do differently were I to build the layout again?
I would probably not use IKEA table tops as baseboards. They have proved to be too large and too heavy to transport and erect easily. They have also started to sag, which is not surprising as they basically consist of two layers of hardboard separated by corrugated cardboard. I would build the baseboards in a conventional manner but as light-weight as possible.
I would not use Markway turnouts. I have not been happy with the way they are gapped and have had to modify them considerably. I would build the turnouts from scratch despite the time it would take.
Never again will I use a mixture of Liquid Lead and PVA glue as ballast in my locos. The reaction between the two materials is causing some of my best locos to burst apart and I have not yet found a cure. If anyone knows how to cure this problem please let me know.
One final thing I would try to avoid is being positioned next to a live steam layout at an exhibition. It happened to me once and everything, the track, the rolling stock, the scenery and the operators all became covered in a film of oil and grime.
That's about it, but as the layout took about 10 years to build the chance of me starting again are probably nil. I will stick with what I have, warts and all.