At the beginning of a game, the Protoss are at severe risk of being immediately attacked by the Zerg. You should have enough time to get just enough units produced to fend off any attacks by the enemy before he finds you.  However, you have to work quickly.  Very quickly.  As soon as the game starts, tell all four of your probes to mine minerals and order your Nexus to make a probe.  As soon as that probe is finished, order him to mine minerals.  As soon as possible, make another probe.  While the probe is being produced, you should have sufficient minerals to make another.  When the first probe is done, have him warp in a pylon and then mine minerals.  Before the probe still in construction is finished, get another probe in queue.  When the next probe is finished, have him warp in a Gateway, two of them of you have the minerals, then order him to mine minerals.  From now on, always keep at least two probes in production, but no more than three so as not to use up your resources too quickly.  When the next probe gets done, have him make a couple of more Gateways and another pylon.  Then have him mine minerals.  Have each Probe that is constructed mine minerals.  As soon as your first coupld of Gateways get finished, have them each make one Zealot.  When the next probe gets done, have him make some more Gateways and Pylons until you run out of minerals.  Keep him by where you are making your buildings.  (Make sure you establish some sort of pattern in your base so that you don't get confused as to where everything is at.  Also, a base constructed in a formation is much better in efficiency as far as room goes.)  Keep Zealots constantly in production in all of your Gateways.  Also, keep making Pylons and Gateways.  When you get enough minerals, cover all of the Vespene Geysers covered with Assimilators.  Also, get a Cybernetics Core in the works.  Make sure you keep making probes, but now you should have enough minerals to constantly keep 5 Probes in queue.  Now when probes get done, have them start mining Vespene Gas.  By now, your Cybernetics Core should be finished, so stop issuing new orders to make Zealots.  Instead, tell your Gateways to make Dragoons.  At the Cybernetics Core, increase the Dragoon's attack range.  Keep on making Dragoons and Gateways. By now, you should have found the enemy with some zealots.  Attack your enemy.  You could actually start attacking a lot earlier if you want to with your Zealots.  Keep in mind, however, that every unit you attack your enemy with is one less unit that you have to defend your base.  When you start attacking, attack constantly; don't let up.  You should have enough Gateways and enough Minerals and Gas to constantly produce Dragoons.  As soon as the dragoons get done, send them over to the enemy's base.  Now you can start building advanced buildings.  First off, build a Citadel of Adun.  Then, warp in a few Stargates.  After that, a Robotics Facility.  By now, you should have almost a constant line now going from your base to the enemy.  With any luck and skill, the enemy won't be able to push back, and you will eventually conquer him.  However, if someone has more units than you, they may be able to push back right into your base, so make sure that you keep producing.  When your Citadel of Adun finishes, increase the Zealot speed and warp in a Templar Archives.  When your Robotics Facility is done, warp in an observatory and a Robotics Support Bay.  When the Stargates are done, warp in some scouts and a Fleet Beacon.  When the Fleet Beacon and the Templar Archives are finished, warp in an Arbiter Tribunal.  At the Stargate, increase the Scout's speed first.  At the Templar Archives, research the Psionic Storm First.  Now make about 12 Templars so that you can select them in a group.  When the Psionic storm finishes, use that ability.  If the enemy is coming after you with a few Battle Cruisers or Carriers, then a couple of Storms from all 12 Templar can kill them almost instantly.  Just select all 12 Templar at the same time, and Psionic Storm the Carriers or Battlecruisers a couple of times, and that should finish them off.  As soon as the Observatory is finished, make at least three observers at the Robotics Facility.  When the Arbiter Tribunal is done, research the Recall ability first.  Arbiters can be a very powerful foe when used in the correct way.  Often times, your enemy will leave the side to their base open to air attacks.  If this is the case, take in an Arbiter and use Recall to warp a whole bunch of Dragoons into the enemy's base right over their main base.  If this sneak attack doesn't succeed in eliminating the enemy, it will severely cripple them, and they will not be able to completely recover for the rest of the game.  Learn to use all of the Protoss's abilities effectively.  Remember to constantly keep on the attack, and with some aquired skill, you should be just fine.

NO-RUSH STRATEGY HERE