That depends on multiple factors, but you could try a third-party tool that optimizes your map or you could avoid loading many variables and having multiple actions in Map Initialization. Share them between the events Map Initialization and Game-time is equal to 0.
Finally, if you have many doodads, you have to reduce them. Sometimes I see unnecessarily spammed doodads in the maps and while it is thought that they look cool or natural, well, they don't.