What can I do between the wall and my streamer/DAC?

I have AT&T fiberoptic internet and the AT&T supplied router. I then have generic ethernet cable to the music room in the basement to the back of my Lumin T2. Is the anything I can do to make this a better sounding situation? I feel it sound very good as is, just wondering if I am leaving some goodness on the table with this set-up, Thanks, Allen.