Honestly, not a thing.
My only advice for those that venture down this road...
Make a plan, scrutinize the hell out of it, toss it in the garbage, rinse-repeat.
Focus not on features but floor plan/layout/flow.
If you continue to come up with the same plan, you might very well know what you want.
Then realize just how much time/effort/pain goes into such a venture.
Done right, you will have something that you will enjoy and will last the test of time.
Done not-so-right, you will struggle to finish, rush to finish, or abandon it all together.
I started my build Dec 2012. It was a weekend/evening project, that was back-burnered a few times.
It was finally drug out of the shop June 2014, and has been on the road since, with countless nights in it, and 75k+ miles of travel.
Best i can tell, its no worse for wear.
I have updated a few systems in that time, mainly electrical, and fancy electric jacks, but that's it.
And most recently, we upgraded trucks.
Beyond happy with it, and it is a big part of our end-game.
Within the next 5-8 years we will cut the cord and hit the road full time, and this will be what we call home.