1. Sniper Teams
Air units are incredibly good at picking off individual units that either stray too far or are otherwise isolated. The goal of a sniper team is "one shot, one kill" and so ideally you need to build sniper teams that have a combined DPS that exceeds the target's hit points. A classic example of this is using stacked Mutalings to snipe workers. For example: you need 5 Mutas to snipe a Probe/Drone and 7 Mutas to snipe an SCV. To flip it, 8 Scouts are needed to snipe 1 Overlord. Conventional wisdom might suggest Corsairs are more useful in this regard (due to a high DPS), but it takes upwards of 12+ Corsairs to snipe a single Overlord. While a handful of Corsairs can be equally deadly, you have to factor in DPS and opponent response/defense. You may only have just a few seconds for each snipe, so you have to make them count. It might be better then to use Scouts instead, because 4 Scouts can take down an Overlord in a couple of seconds OR they can also be used to snipe Drones!
2. Engaging Static Defenses
For larger targets that require prolonged attacking, DPS can make all the difference in the world. The reason why a bunker with a single marine and an SCV repairing it can hold off a dragoon (with range) is because the Dragoon's DPS (15.873) cannot outpace the SCV's repair rate (16.57 HP/sec), and thus 2 Dragoons are needed. This can lead to a hilarious standoff in which multiple SCVs are repairing a single bunker getting attacked by multiple Dragoons. In this scenario, the Protoss player ought to simply trade fire to damage the SCVs until the balance returns to his favor.
3. Kamikaze Dropping
Kamikaze dropping is sending in a transport loaded with troops that you have no intention on bringing back. Ideally, these would be cheap units with good DPS, such as Marines, Vultures, Zealots, Zerglings, and Hydras (especially after upgrades). It is tempting to push for an early tech unit drop that uses Reavers/DT/Lurkers/Tanks, but if you have specific targets in mind, you can actually do more damage with cheaper units by delaying a drop slightly. Conventional wisdom suggests that drops should be focused on killing workers, as this will degrade your opponent's economy. However, what if you went after some more integral structures? My proposal, is to develop a drop strategy that seeks to make base destruction the primary goal. This strategy won't be particularly useful against Terrans, because Command Centers can lift off, so I wanted to crunch the numbers for you and show you how killing a Hatchery or Nexus can be far more effective.
Let's start off with a some assumptions:
a) These drops work particularly well against players who over-defend their expo and leave their main exposed.
b) If your opponent has high APM or pays attention to the minimap, it will still take him roughly 1 second to see a drop is coming.
c) It will probably take about 5-7 seconds to get first responders onto the scene in order to attack your dropped units.
d) Based on this, the goal here is to do as much damage as you can in 7 seconds, knowing your units will get picked off one by one as soon as you drop.
e) Target HP / DPS = number of seconds it takes to kill
>> Kamikaze Zealots
PvZ -- Hatchery 1250 vs Zealot 17.316 = 72.187 seconds
72.187 / 12 Zealots = 6.01 seconds
PvP -- Nexus 1500 vs Zealot 17.316 = 86.62 seconds
86.62 seconds/ 12 Zealots = 7.21 seconds
The benefits of going after a Hatchery/Nexus is that it can degrade resource gathering significantly if the workers don't have a nearby place to go. A saturated geyser yields about 288 gas per minute, while 18 drones/probes yield about 1217 minerals per minute. Given that it takes 1:15 to build a new Hatchery/Nexus, you'll be blocking a huge resource draw -- far more than perhaps just by killing workers alone. You also have to consider the cost of a new Hatchery/Nexus, which is pouring salt on the wound. The Zealot Drop itself only costs 1200 Mineral (because the Shuttles can be repurposed later on), and if the attack is successful it could be a precursor for a direct front door attack or a 2nd shuttle drop. This kind of drop can also occur in the early game using 1 Base only, and could even be expedited by going 2xRobo (which is doable because nothing else will cost gas up to that point). You should already be building Zealots anyway in PvZ, so it's not that big of stretch. At the very least, even if your opponent gets the jump on your drop, 12 Zealots can easily trade their value in kills, which will force the opponent player to delay his attack (which will buy you time to tech up to anything you want) or rethink his entire strategy.
BTW --- Firebats have the same DPS as Zealots, and so in theory a Terran equivalent of this drop would actually be cheaper and could arrive much sooner.
Anyway, that's all I got for now. Hopefully these (theoretical) applications of sniper teams, demolition squads, and kamikaze drops will give you some ideas!! If you use them, please save and post the replay!