good

Attack with small groups (from 1 to 15 units): You must concentrate fire in one of the enemy units untill you kill it, then concentrate in a second unit and so on... Select your whole group and click the weakest enemy unit first. Kill the weakest first (execpt for sonics that are strong, but must be killed first), then go for the strongest ones.

Basically its this: Over run infantry, kill sonics or deviators, kill quads, kill missile tanks, kill siege tanks, kill combat tanks, kill trikes or riders, and the last kill devastators.

Attack with big groups (from 16 to 64 units): Line up and group your units near (but still not in the range of) the enemy group. You must put your long range weaponry (missile tanks, sonics and deviators) on the front line.Select the whole group and click on the closest enemy unit and when your units start shooting press S (stop) on the keyboard. When stopped your units will shoot every enemy in their range. As soon as you kill the first units press G (guarding) on the keyboard to advance against enemy units again. When your units start shooting press S again and keep alternating between G and S to aproach and attack in the right timing.