Noise and timing are the two main issues affecting streaming quality. Take care of your noise issues, lower noise floor means higher resolving/transparency. Take care of your timing issues, far closer to a continuous analog wave form, this results in more analog like sound. As for the equipment, cabling etc, everything matters, any weak link in chain affects the entire chain.
Now as for where to start. So lets say you go for dac first, problem is if you have crap going in dac is not performing to highest potential. You can also start at the beginning of chain, so feeding dac with lowest noise floor, most precise timing, if dac weaker link not getting full potential of feed to it.
Point is I've found every single link in chain important, just a matter of priorities. I'd suggest starting with dac and streamer as the most efficient way to achieve high quality streams. Spend absolutely the most you can afford here, tweak away for everything else. As for tweaks, I've found purpose built audio components superior to the generic stuff. LPS for every single tweak that requires AC quality fiber conversion or fiber service great for noise reduction, don't cheap out on any of this. Finally timing, I've found master clocks are extremely critical for trying to achieve a continuous analog wave form such as found in analog souces. I personally will never purchase another dac without I2S input, or proof/evidence that dac master clock and power supply to that clock are of highest quality.