With my time of playing as the Zerg, the Queen has been my major area for spying. I use them all the time for going up to enemy units, and using parasite's to see what they are doing. There is a little secret I have kinda developed, some may also have noticed this, sometimes have you ever got a base that was really big, and you were not able to keep watch on all of it? Well, this is a risky, and chance kinda thing to do, but, what you do, is parasite a new expansion of the enemy, if you are lucky, which I am not, the enemy will not see what you are doing, just meerly here the sound of a parasite going off. Now, unless you enemy is like balistic about finding the parasite, he will not even think twice about it. If it gets futher, that expansion will grow and you will be able to see its weakness's. Now you might wonder, well what good is it when you don't attack but watch. That is wrong, you need to attack his main base, detect it, and throw relentless attacks against it. Once you start to really stress him out in that area, have a group of ready attackers, wait outside his main base, then, get another group at his expansion. If you are a good player, unlike me, you should be able to pull this next step off. What you need to do, is attack at the same time, but, when you attack the expansion, plan ahead, make sure you hit the areas that are not gaurded, and hit him hard. Attack with both groups at once, this will cause confusion to the enemy. He will only be able to be fighting at one of his bases. The units will attack by themselves, but, what if the second base he is not watching, has like a ton of bunkers that are out of reach? He will not be able to pay attention to that battle, and click it on the mini map, and remove the marines from the bunker. Lets just say, this is a risky thing to pull off, but, in your case, what would you have to lose...wait, everything. If this kinda plan does not work, then, you might want to hope that he does not have the power to retaliate. If this is so, you might want to wish that you built back up forces in your base, and your base is armed with some type of defense. Good luck if you can pull this maneuver off, cause if you can, your good.