Ok this is one of my favorite units in the game, just because it can cast psionic storm for only 75 energy. It's the best spell for taking out masses of enemy units. Easily the best unit for taking out workers quick and fast. These units are the best for offense and defense. Being able to create archons isn't a bad ability either.
Now to use these guys, you gotta realize that they're slow, so it's best to get them spread out to cover as much area. Second, they have no attack, so trying to take down structures with these guys isn't a good idea. Psionic storm should be casted on the first unit not the center of the group. This is because the units will react by running through the storm to attack your templar. You should then cast another in front of your templar to finish off any units that survived. Try holding shift and casting the spell using 't', then release shift. This will make the templar cast at those spots, like waypoints. makes it easier if you can predict how your enemy will move his troops.
Best thing about psionic storm is that it causes chaos, making your enemy run around trying to get out. This of course helps you since you can get free shots at your enemy's units. Just try to stay away from melee units.
Hallucination is a decent spell for making your real units to survive. Best used on scouts, shuttles, and zealots because they're all fast units and don't take up too much room, if you make masses of them. It's best to use hallucinate against a Terran who has a strong choke point. This should allow you to get more hits in with your dragoons and reavers, as your real and fake zealots take hits. It also helps to drop on islands, where the air defense will normally kill your shuttles. You can also hallucinate a critter and take it into an enemy base, but be warned anything that "auto-attacks" will do so, and any straight movements in a base may cause suspicion, keep it natural.
Archons are very strong, since they can be created early. There best asset is their splash damage, which makes mutalisks and zerglings die very fast. I would only use these units if you are lacking dragoons or corsairs. Unfortunately, they are basically all shields and shields absorb full damage from everything. Try not to use archons, because 2 templars are more valuable. If you do use Archons in masses, be sure to fully upgrade the weapons and MOST importantly, the shields upgrade since they are all shields.
