Even before any scene is set, there's lots of "ground work" to be done - no pun intended.  Grassy areas - even if there are trees planned - are prepared with some sense of raggedness.  I usually add a bit of "rougher" grasses to my initial dusting of turf, even through, when the trees are "planted", most of this roughage won't be visible. 

Open ground starts out as a layer of Elmers glue spread evenly.  On to that, I usually sprinkle several variations of brown decorator sand, and then a denser layer of very fine brown ballast.  Over the years I have collected a number of small bags of blackish and greenish-gray "dirts" - I have no idea from where, but I sprinkle those here and there about the ground area for "shading".  I usually wind up wetting these areas down with soapy water and then misting them with "scenic cement", all the while adding more sprinklings of scenic dirt.   

Once I'm satisfied with the earth tones, I vacuum the tracks and ballast the road bed before moving on to further scenery.

However, from out of the disarray comes a bit of clarity.  First task is structure placement.  After a bit of "ground work" around the bases of the buildings it will be time to start with all the details - everything from vehicles to people to bushes to trees, etc.

I learned early to work on one scene at a time - inexperienced modelers are prone to try and fix everything at once.  Problem is - you lose track of the job.  Problem is - you lose track of the job.  Problem is - you . . .

Even with what appears to be a large oil spill in the center of the layout, the cement complex takes shape on the left side of the new addition.  Eventually - though probably not before next summer - there IS a plan for a scenic element on top of that access hatch.