start with a single voice and all the support modules that are needed for that - but instead of buying a single vca, buy a quad etc etc etc get to know them inside out and then add as needed as slowly as possible
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities