Once you have a compatible set of components that sound great together, speaker wire, interconnects and powercords can make a very significant improvement in sound quality. The better your system, in general, the bigger the improvement you are likely to experience. But also, experience developing listening skills will reveal aspects to sound quality you will unlikely have even noticed when you started out.
One truth that has shown itself to me over and over again is that there are lots of good sounding systems, but all the truly great sounding systems have been meticulously tweaked through wires, vibration control, and room treatments in order to get their sound.
While the is no real wrong way. Most of us do components, wires, then room treatments.