How to beat Tau
Close combat will beat Tau everytime, believe me I know. I've been playing Tau for a few years now. They were my first, and still favorite army. Little dudes with reallly big guns.
I use basic crisis suits with twin linked weapons, shield drones, team leader for leadership, bonding knife, and shield drone needs. Save the shield generator for your Shas'O as you need to keep points down in order to take specialized crisis teams ( usually 2 per team) Fusion blasters and plasma rifles are great MEQ and HQ killers. Burst cannon for lighter guys such as guard and gaunts. Keep a unit of gun drones in front of them for forcing target priority tests, pinning tests, and blocking close combat (a must). Keep the suits moving and in cover if possible. Use the assault move to back away from anything heavy and remember to shoot at something until it is dead. Even a SM scout left standing can ruin your day.