Yup, you can fiddle with the settings to make it less hungry,.. but on the whole, Sketchup can just get 'heavy' really fast if you work on detailed models, as I have found. You can't 'debug' anything about that, it's just the way it is.
You need plenty of resources when your models get into the high polycounts and if you dont have them, it stops at one point and will behave like you experience. I have a truckload of resources and even then sketchup will do the 'no response' thing for a while if I copy some detailed or large stuff, or on auto saving huge models.
What I would also suggest, is first of all to of course work with components/groups, cause that's always best.. But then just Hide any groups or components that you are not actively working on. Because sketchup continuesly renders everything, so not having to render most of the model - that's not being worked on anyway - makes it run much much faster.
For the much larger things that you can't get around, just let it rattle for a while.. dont go pressing keys or clicking things in a frenzy, that might indeed make it crash. I found that just letting it go and leaving it be for a bit, means it will complete the action it's doing.
