If you click on the quick menu with the gears icon in the top left of the screen, and then open the Manage Properties window, you will be able to edit your lot. This will automatically take you to where your lot is to work on it.

look at the manage property tab on the cog under your level, click edit and that'll show your current property. If you're seeing a construction site then look between 1A0 and 0A0 as thats the only one I can see, if it's a built casino try the one north of the central plaza as it's the only closed one I could find. Alternatively pop into each zone real estate building and look at the map/desk, your property will show as grey/blue outlined plot rather than black, red or green plot.