From personal experience with and against Tau:
Your battle plan revolves around Explorers. As long as Explorers are operational, battle is yours, but when you start losing them, you lose the battle. Thing is, you WILL have more ordnance than enemy. Therefore, in this aspect of the battle, he will be in defensive position. If you lose this advantage, he outpaces, outmanouvers and probably outguns you.
But with masive ordnance superiority Tau can achieve, you mitigate it. You force him to spent time braced, to reload his own fighters instead of locking on or coming to new heading.. His advantages disappear.
Therefore, guard your Explorers, it's your one sole priority in battle, because it's the Explorers that allow other ships to win (And, in case of low-turret enemy vessels, they will destroy them on their own)
Second of all - when it comes to special order priority, do your best to keep battlefield fully saturated with ordnance all the time. Every time siginificant amout of it gets used up or destroyed, reload. Keep your explorers away from the main battle, behind rest of your fleet. Braced explorer does not reload, so whenever enemy forces you to do it, he gets a bit of breathing space next round and you may not allow it to happen.
Remember that explorer has lots of hits - he can take a few and keep fighting. Don't brace them unless something significant hits them.
Do not separate your ships. Mind the formation, with combat ships in the front and carriers in the back, but keep them close to each other. You need ability to mass your firepower, and you don't have mobility to do it when formation breaks. Unless enemy has significant advantage on extreme ranges, such as multiple nova cannons, do not close faster than necessary. Just send ordnance forcing him to come to you.