Tips on horse archer vs horse archer combat

[Unintended BM]

I can beat the crap out of the Seleucids and the other infantry based factions in the area, but I suck at fighting other horse archers. This basically limits me to Pahlava because they're the closest to the Seleucids and probably the easiest horse archer faction, but I'd like to try the Saka or the Sarmatians. So, any tips for fighting horse archers with other horse archers? It seems like it'd be easy, but I get way more casualties than fighting infantry.