I've started fleshing out the neighborhood where someone set up a large coarse retail district, I'm refining the edges and adding some residential too at different levels of detail to see what works. No way I'm going to do a huge area but maybe someone will get inspired or I'll figure out easier methods. I'm tagging mostly landuse=retail or residential and frankly, that's a lot of work first sketching off the aerial photos then filling in the tags for each one (can't it remember and repeat what the last one was?).

Probably there's a more suiable interface I don't about know yet... One challenge is learning the behavior of how to edit large polygons, using the scissors tool to crack them open and highlighting nodes to delete, clicking on the loose end to add more, etc. I lost some big outlined areas doing that once! and sometimes they don't quite close so they won't render. It would be great if the edit mode showed open traces different than closed because you can tell until going into view mode.

I did discover that I can get other store types to render by adding a name tag to the building outline which is nice. I'm using google street view for some field checking and just from memory, plus there are a lot of stores shown as point data so I'm moving those points where the front door is in front of the building rather than enter as tags on the building outline. I'm not sure which is the best way to go for that, some playgrounds and parks have both and they render the name twice which is a mess and I deleted the points in those cases, it still puts a playground icon in with the outline tagged properly.

The area I'm working on is 24th and Diamond, you can click the view link below then you need to zoom in. I guess this permalink is more useful: osm.org/?lat=37.751321&lon=-122.435938&zoom=18&layers=M

Here's another person's approach across the country: osm.org/?lat=39.693062&lon=-104.980461&zoom=18&layers=M
I changed a couple buildings from their building=yes to landuse=retail. If I keep their building=yes it just renders a subtle outline so I deleted the building tag on a couple to show the difference.