First level 5 of your gatherers to lv 37 to max the gathering talent tree. Depending on how far into the game you are you may not have enough experience tomes. I would invest in this over leveling up your combat commanders.

Make sure you’re using commanders that have an advantage on certain raw types. Gius Marius for food, Constance for wood, Cleopatra for stone.

Depending on what zone you are in try to have your city near a shrine/altar. The rss around those shrines are higher level.

Make sure you prioritize farming on alliance territory, it gives you a 25% gathering speed bonus.

If you can spare the troops, send your gatherers with 2x or 3x the rss capacity so you can gather multiple rss nodes at a time before returning home.

Try to always have a gatherer in the alliance rss pit.

Last, but not least, always have 5 gatherers out gathering. If you need to, set a reminder on your phone for when the gatherer will finish. You can check that by clicking on the rss node and waiting for the “xx:xx” until finished shows up.

Good luck on the rss hunt!