cartridge first, the best you can afford and that your turntable will support with proper adjustments and net system resonance.
phono stage also needs to support the cartridge with proper gain and loading options.
Relative Importance of Analog Components
We see people struggling with what to upgrade next, or where to direct their attention if everything seems to be working fairly well. I'm probably a bit more inclined to give more importance to sources and less to speakers than most people, but in general I like to look at which component is the 'rate-limiting factor' which one holds back the rest and then concentrate on improving that.
But to look specifically at vinyl reproduction, I have the strong impression that out of the four main components, they can be ordered in importance of potential effect on sound like this:
Cartridge
Phono stage
Tonearm
Turntable
I'm sure other people would list those four in a different order. How would you rank them and why?