Pincushion

Hit an enemy with 3 arrows, without killing them.

For the first time in your career as a Sniper, you will thank enemy Medics for this achievement. It is only by their good graces that you will manage to get three arrows into an enemy without them dying. The best target for this is a Heavy that is being healed, as the overheal on the Heavy will allow him to survive all three shots without requiring more healing. So simply stay on the lookout for a Heavy and Medic pair, then fill them full of arrows! Naturally, the best place to do this is while on the balcony or in the entryway of 2fort with the Huntsman.

To farm this, have a friend play as the Heavy and another friend play as a Medic. Have the Medic overheal the Heavy, then shoot three arrows into the Heavy consecutively. The Heavy should stay alive, and you'll get the achievement! If you want, you can also get William Tell Overkill by getting an arrow headshot on the Heavy. and pinning him to the wall by his big russian noggin.

Note: You can do anything else to the enemy both before and in-between sticking him with arrows. The only requirement is that the enemy must be alive while three arrows stick out of his body. Preferably in funny ways!

Rain on Their Parade

Jarate an enemy and the Medic healing him.

Yet more Jarate achievements! This achievement has you drenching both a Medic and his buddy. Naturally, this is best used on a Medic and Heavy pair that is busy rushing your base. A great way to get this is to quietly observe the pair as they invulnerability charge through your defenses. As soon as the über wears off, hit them with your Jarate. It's both an easy achievement and it will help blunt the rush through your base, as your teammates will make short work of the weakened enemies.

Farming this achievement is pretty much exactly like Pincushion, only replace shooting the pair with arrows to hitting them with Jarate. Therefore, this achievement is best farmed with William Tell Overkill as well as Pincushion, thanks to having a handy dandy Medic and Heavy pair there for you to experiment on! You might also consider getting Number One Assistant as well, if you have another friend with you that can play on your team.

Note: This achievement can be done with any Medic pair. The MEdic and Heav pair is just the most traditional and most common pair out of them all.

Robbin' Hood

Take down an intelligence carrier with a single arrow.

A relatively hard achievement, you will almost always have to get this by killing a Scout. THe easiest way is to watch for Scouts taking the upper path, which is common on just about any CTF map as there are not as many people up there. The roof in the middle of 2fort and the train cars in Well are two great examples. Simply sit and watch for the Scout, and as soon as they should up, put an arrow through their head. It'll be difficult, thanks mostly to the incredible movement speed of the Scout, but you can pull it off!

To farm this achievement, sit in the intelligence room as one of your friends shows up as a Scout. Have him grab the intel, then line up your arrow and ace him as he stands still for you. If you want, you can try getting this achievement with Parting Shot (by having a Medic make the Scout invulnerable right before getting the intel) or Not A Crazed Gunman, Dad (by having the Scout continually get the intel while you continually kill him, racking up 3 objective defenses in a single life).

Note: The carrier does not have to be undamaged when you kill them. You can kill a carrier that has been weakened by teammates to get the achievement, if you so wish. However, if you weaken the carrier with, say, and SMG, it won't count. This only counts after the intel has been picked up, so they can be weakened before getting the intel, then killed after they get it and it will count.

Rode Hard, Put Away Wet

Jarate an enemy that you're dominating.

Seems like the developers really love Jarate, and they want you to use it. A lot. We're talking a full eight out of 35 achievements that revolve around an unlockable weapon. That's unheard of! Anyway, this achievement is a little difficult for a Sniper, as chances are you will never be close enough to a dominated enemy to throw the Jarate on him in the first place! Therefore, the best way to strive for this achievement is to Jarate an enemy Spy that you have killed multiple times. You'll need to be alert enough to see enemy Spies, but if you can get one multiple times without dying and then Jarate him, you'll get the achievement.

To farm this, do any of the achievements that require you to kill people, such as Self-destruct Sequence or Jarate Chop. Doing those achievements will inevitably net you a big fat domination, which you can then go use your Jarate on. A relatively easy achievement to farm, assuming you are doing other achievements at the same time (which you should be).

Note: You can be dominating the enemy through any method, including (ironically) domination by Jarate assists. There's nothing quite as humiliating by getting hit by Jarate five times in a row.

Saturation Bombing

Jarate 4 enemy players with a single throw.

Will they stop with the Jarate achievements? Apparently so, as this is the last of the Jarate achievements and the one that is arguably (next to Number One Assistant) the easiest to get, either by normal gameplay or by farming. In normal gameplay, this achievement is easily acquired by simply staying up on the balcony of any map and waiting for a concentrated rush. As soon as they rush towards the objective in a group, throw your Jarate at them. Easy achievement! There is no point in farming Saturation Bombing, as it is so easy to get it normally. Goes well with Rode Hard, Put Away Wet (as chances are you are dominating one of the group) as well as Number One Assistant.

Note: Nobody will be upset with you if you happen to get more than four enemies with a single throw of your Jarate. So don't fret about getting exactly 4 enemies hit.