Just to add to what people have said,

Break it down an plan the hell out of it, make little test scenes for the bits you need so you've got a plan of action.

When modeling remember to think about how close to the camera parts are needed, if there far ways dont model the hell out of them.

Chrone - Nparticles have somre pretty great features not just "for colliding with stuff" its also got a liquid preset setting that may be of help for this.