Split Formation. Keeping a mobile Tau army in one big block might be tempting due to its ability to provide immediately concentrated fire, but it's unwise in the long run. Splitting your force into several detachments multiplies the number of things for your opponent to worry about, which is always good.

Doing this split with your forces also makes it possible to flank your enemy. Keep an enemy hiding behind cover with one detachment's firepower while another one moves around for an unobstructed shot. You can also use Pinning weapons in this manoeuvre to deadly effect. Just don't forget the objectives while you're busy flanking.

Be careful, though. If you split your force into detachments that are too small to be effective, they may get picked apart by the enemy before you can bring in other detachments to support them. The more you split your forces, the better your timing must be to concentrate their firepower.

The Power of Fear. Most opponents have a near-irrational fear many weapons and systems in the Tau arsenal. Battlesuits, Railguns, Seeker Missiles, and Markerlights all strike terror — or frustration, at least — into many foes. Use this real-world psychology to your advantage. The mere presence or fire arcs of these units can be enough to drive your enemy into cover. Hopefully you can time it so your Fire Warriors (or another "innocuous" unit) are waiting for them when they flee in this manner. Remember, you don't always have to be shooting to be effective.

Sometimes, this psychological warfare can dictate your target selection. Though it might be a waste of a Railgun shot when other targets are available, you can aim one with a few Markerlights at the character who means the most to your foe. Watch the fear (or anger) grab hold of his eyes when his number-one guy or vehicle explodes in a cloud of vapour.

In fact, one of the best way to counter the infantry-based Heavy Weapons (Lascannons) your enemy might take is by forcing them to move each turn. Deploy your Hammerheads with Railguns in the corners of your table edge (or some other place that's out of range of his Heavies) and drop a few submunitions on their heads. When your opponent realizes that you have a gun that can hit his most powerful weapon without any danger of retaliation (your range is longer), watch him start to move.

Another way to get under your opponent's skin is to deny him any sanctuary. Though there might not be a target sitting there when you move, slide up a few Tau units so they have a fire arc behind the best cover the enemy could use.

Know What You Can Do. In the heat of battle, it's very easy to forget important abilities of your mobile Tau force, and you should assume that your foe will not remind you. Don't forget that Skimmers can move over any terrain feature as well as end their move hovering over Difficult or Impassable Terrain (though you can't stop over other models). You can really surprise enemies who field non-Skimmer armies when you cruise right over the cover they were depending on to block line-of-sight. Also remember that you should always move your Skimmers 6" or more to get the protective benefits of moving fast (plan your vehicle upgrades accordingly — Hammerheads should have Multitrackers, for example, so they can keep moving and still shoot). Lastly, don't forget that you probably have a lot of units that can Deep Strike. Dropping your tank hunters or infantry sweepers behind the enemy line, especially with the help of Pathfinder Marker Beacons, can really throw your enemy into a panic.

That last idea can be necessary in a mobile Tau force, as it is unlikely that you'll have many XV88 Broadside Battlesuits to take down vehicles. Broadsides can't keep up with your mobile force, and your Hammerheads can't eliminate large numbers of vehicles. Thus, Deep Striking a Battlesuit Team or sending in Piranhas can become your best anti-vehicle techniques for mobile Tau.