Artillery

When you want to effect some punishment for those pesky enemies of yours, you'll be able to call down artillery strikes on them. Although powerful, these strikes are relatively inaccurate, take a while to hit after being called for, and will impact nearby obstacles, such as buildings and structures, meaning that not all of them will actually hit the ground that you're aiming at. Still, the explosive radius on each shell is large, making this an effective anti-infantry ability, especially if you have a target that insists on camping out-of-doors, such as a sniper up in the hills. It can also be used on tanks, although you will usually need more than one direct hit to kill off a fully-armored vehicle. Still, though, when something's sitting still, a little artillery fire can go a long way to letting them know that you'd appreciate it if they moved.

Artillery fire can also be used to clear a path for your infantry or vehicles as they attempt to maneuver towards a defended flag. Laying down artillery fire will, if not kill the defenders, at least weaken them and force them to go to ground for a moment, giving your teammates a perfect opportunity to run in, finish them off, and capture the position. This requires some pretty close coordination, obviously, but is perfectly doable, especially if you're coordinating yourselves via voice communication.

Don't forget to zoom in on the map to witness the splendors of your artillery for yourself.

You can also fire artillery as a defensive measure, when enemies are attempting to overrun an undefended flag of yours. The flag capture radius is fairly close in Battlefield 2, meaning that most enemies will have to be within ten meters or so of a flag before they're able to convert it, which is well within the explosive range of an artillery barrage.

Lastly, artillery can sometimes be used as a deterrent, when a single foe is being a pain. This is especially true of snipers, who'll often sit atop large buildings and go to town; if you can spot them, then artillery should be able to finish them off without requiring you to call out an airplane or counter-sniper.

Note that it takes 10-15 seconds after calling for artillery for it to actually start hitting the ground, so you shouldn't expect immediate results from it. Hitting moving enemies is quite difficult; it's more useful for pounding the snot out of enemies when you know precisely where they'll be, which most often occurs around flags.

Predator UAV Deployment

When you need real-time surveillance of an area, then the UAV option is your best bet. Instead of a simple satellite scan, this option will send down an Unmanned Aerial Vehicle to a location that you click to, and give you eyes on everything that occurs in that location for a certain length of time. UAVs can't be seen by players, so they can't be shot down, but they don't last forever, so take advantage of the information that they give you while it lasts. What's more, enemy locations ferreted out by UAVs will be relayed to all players on your team, so that everyone on the ground will get the benefit of your intel.

UAVs are, obviously, best used in the area around a contested flag, whether you're attempting to capture it or defend it. Most flags in Battlefield 2 are going to have a number of buildings or other hiding spots nearby, and a UAV scan can clue your players into the location of enemy snipers or incoming armor far better than verbal notes that have to be passed down the chain of command. UAV scans will also distinguish between infantry, armor, APCs, helicopters, and planes, giving each kind of vehicle its own icon on the minimap, which is something that the normal Scan command can't do.

In general, you want to have a UAV up at all times. They last for around 50 seconds and have a respawn time of 60 seconds, so you'll be able to launch another one quite quickly after the previous one runs low on fuel. If you can't find a hotspot to lay one down, ask your squad leaders if they need one somewhere, or just plop one over an undefended base to see if there are any foes around.