I have a beginning project built for an RTS. It is a scrollable, zoomable background with main and GUI layers, and includes a clickable mini-map.
So just consider that this project will be a simple form of tower defense. The scroll and zoom aren't really required at this point.
Consider player objects are fixed. These would initially just be a tower-type of object. (A GUI for placing those, and additional variety can come later and is not really in the scope of this example, at least not yet.) For now, let's just do whatever is easiest, such as pre-create those programmatically. Need to spawn enemies as well, which move toward target (center of map). Assume that enemies are 'fliers', so they move without need for complex path-finding for now. Player base is at center of map. A consideration is that enemies would be created in waves, but I'm not sure that is really a big factor in the structure of tracking and handling them, only in the initial spawning of them. So that might be out of the scope of this example too.
I would like to be able to easily increase and extend the types of player and enemy objects as development continues.
I figure this is a fairly simple learning project, but useful for the style of game I am trying to create.
(I'd also like to put the whole experience of this learning project into a tutorial series, since I would like to encourage others to come up with some good RTS games.)