Reconnaissance

Overview
In reality, Spies are often used to gather information on rival operations or businesses via infiltration. In Team Fortress 2, it is no different. With the tools at the Spy's disposal, reconnaissance for your team is a feat that is easily done, and always useful for your team. This tactic is mostly used on attack/defend (CP) maps on offense, (PL/PLR) maps on offense and (TC) maps.

Tools

 * Watch used: Cloak and Dagger/Invisibilty Watch
 * Primary Weapon: N/A (Passive tactic)
 * Aim: To gather information about enemy emplacements and incoming enemy classes.

Section 1: Infiltration
Using your Cloak and Dagger or Invisibility Watch, proceed from your spawn through the enemy lines towards the objective (which can be a Capture point on (CP/PL/PLR/TC) or the enemy base's intel room in (CTF).) Recharge your Invisibilty Watch by ammo packs, or your Cloak and Dagger by remaining stationary.

The depth of your infiltration can vary, all depending on where the enemy is at the time of your infiltration. For example, on a Payload map, from the round start, the enemy will usually be bunched around your spawn, along with Sentry nests covering the first capture point of the cart, in order to impede your process. Your infiltration would mostly be useful in quickly positioning yourself somewhere with a fairly clear overview of the first point, so you can direct your team to threats before they get killed. However, you do lose the ability to warn them about enemy classes coming from spawn; which may be superfluous in itself due to the usual abundance of teleporters available for the defending team. Later on in the match, the cart will most likely hit the first point; in which case, your infiltration would need to be much further into enemy territory to see where the new sentries are being set up, and which classes are coming towards the cart.

Section 2: Positioning
Once past the enemy lines, find a spot where you can observe the enemy from. Map specific places aside, the usual good spots are:
 * Upon crates, barrels, rock formations or doorways (if possible). The more off the ground you are, the less likely you are to be randomly spychecked.
 * Away from high trafficked choke-points. While you want to observe the enemy, you don't need to be dangerously close to them. Having a general overview does not require being right behind the enemy.

With the Cloak and Dagger, invisibility shouldn't be a problem, with its ability to recharge by remaining stationary. However, for the Invisibility Watch, you need to be positioned close to Ammo Packs to constantly recharge cloak. But be warned; enemy Engineers will begin taking any ammo pack in the vicinity, and while potentially hampering for them by taking the packs in their vicinity, you are at a great risk of being bumped into whilst attempting to grab them, so it is advised to move away from the area they are building in.

Section 3: Reconnaissance
When in position, you may ask yourself "What should I look out for?" Generally, the things to look out for are:


 * Engineer Nests. Save your teammates the trouble and time wasted in respawn after running into an Engineer nest. Notify your team as soon as possible about the location of the nest, number of sentries in them and the level they are at, teleporters and their level, dispensers and their level, how many Engineers are in the nest, and if there are any other classes defending the nest. From there, you can either co-ordinate a Sapping with a rush from your team, or simply observe some more.
 * Heavy/Medic Combos. A deadly pair, but usually only when they have the element of surprise. Rob them of that element, notify your teammates where you saw them, which direction they were heading and, if particularly vigilant, the uber/kritz level the Medic had. If he's fully charged, tell your team to run, or guard your Engineer.
 * Snipers. Keep the heavies happy. Notify them of how many Snipers there are, and where they are aiming their rifles at. Perhaps suggest an alternative route to them, or ask for a friendly Sniper to take them out.
 * Spies. Just as you are deadly to the enemy, their Spies are deadly to you and your team. Take note of their disguised class, who they are disguised as and the direction they're heading. Your Heavies, Soldiers, Engineers and Snipers will thank you.
 * Uber/Kritz rushes.  As with Heavy/Medic combos, they're deadliest when they have the element of surprise. Tell your team what class is being ubered, where they're heading, and whether or not it's going to be worth trying to turtle them out, or falling back.
 * Uber/Kritz rushes.  As with Heavy/Medic combos, they're deadliest when they have the element of surprise. Tell your team what class is being ubered, where they're heading, and whether or not it's going to be worth trying to turtle them out, or falling back.

Pros
This technique allows your team to gain inside information about potential threats, and know how to deal with them when the time approaches. They will not be surprised by Sentry nests, Spies, Heavy/Medic combos and Uber/Kritz charges that would normally cripple an offensive rush.

Cons
This technique can be fairly superfluous if they enemy acts fairly predictably. Sentries covering the final point on a (CP/PL/TC/PLR) map is to be expected, and if your team is fairly vigilant, they can counter Spies and Snipers easily. Uber/Kritz charges can have their element of surprise countered with a couple of Pyros airblasting them. And sometimes it is easier trying to take out a lone Engineer and his gun whilst it's being built than simply sitting there, notifying your team about it, and waiting as he upgrades it fully.