Forgetting about reserved spots

[MΛRCUS HΞLIUS]

I wish I could put flags or markers or something down to remind me about spaces I am reserving for Markets, Resorts and stuff like that, I come back to a game and accidentally place a building down and then block the placement of my high scoring buildings.
I can't remember every location I need to place stuff, this is infuriating.

[.MISTY]

As there are no measurements for each building, your flags or markers if they exist in the game, will only be indicators of a reserved location. When it's time to plonk a building there, the building MAY NOT even fit in it. Yeah, it can really be that frustrating.

So, your best chance of not forgetting is by writing on paper what is your planned action for the future with reference to existing buildings. It is an unforgiving game unless you use the save/load method.