After reading posts on this site for years, I'm finally doing a post.
I'm adding some scenery to the new construction side of my layout. This part of the hobby seems to be the most enjoyable, every "mistake" is acceptable, since nature is not perfect. Also I've come to the conclusion that nothing is straight, flat, nor the wrong color. Look outside and study the world we live in, all of have said look at the color of that house, must have been free paint, haven't we? So remember when adding structures, scenery and all those little accents, nothing is wrong. It's your O-scale world, build it, love it and enjoy it.
Just my way of looking at things.
P.S., Dust is natures way of adding some weathering to your layout. And it's free!!!