Kill an enemy soldier while both you and the target are airborne.
This achievement is easiest when you have the Direct Hit, thanks to the automatic criticals on all airborne targets. To get this, simply rocket jump into the air as an enemy soldier is in the air as well. Then kill him. You can do this in any fashion, from shovel to rocket to shotgun, as long as the other Soldier is dead before he hits the ground. If you kill him after you die, such as through a rocket, you'll still get the achievement, so don't worry if you die.
To farm, get a friend to play as Soldier. Then do the exact same farming techniques outline in the Duty Bound achievement. Damage yourself with one rocket, then rocket jump into your buddy and kill him with the Equalizer. This has the effect of getting you both Wings of Glory and Duty Bound. Beyond this, you can also farm Death From Below alongside this achievement, as the guaranteed criticals from the Direct Hit make getting kills a cinch in midair.
Note: This is unlikely the reference made in the achievement name, but there is a classic Origins flight sim by the name of Wings of Glory. As always, it is set in World War 2. It was released on DOS and has not seen re-release since.
Engineer to Eternity
Kill an Engineer as he repairs his sentry gun while it's under enemy fire.
This achievement is a complete reversal of a Medic achievement with a similar goal (heal an Engineer while his gun is under enemy fire). However, you will have a much easier time than the Medic in getting this achievement, thanks to the splash damage from your rockets. Instead of directly attacking the sentry, shoot next to it so that the splash damage hits the Engineer as well. This damage counts as the sentry gun "taking fire", and you can easier kill the Engineer this way. Once you do so, you'll have the achievement.
Farming this achievement is like farming every other Engineer achievement. Get him to build a sentry far away and follow the standard steps to complete the achievement. This is best farmed with Guns of the Navar0wned, as you can destroy the sentry while outside of its range, getting you achievement credits as well as enabling you to continue the grind if you fail to get this achievement.
Note: The references keep on coming with this! This time it's a pun on an Oscar-winning movie by the title of From Here to Eternity. The movie is about the lives of several soldiers set in the days before the attack on Pearl Harbor by Japanese forces. Interestingly enough, it is a combination war movie and boxing movie.
Kill your nemesis with a shovel.
What an achievement. You have to track down the player who has been killing you the most without you doing anything to him and finish him off with your shovel. While this may be difficult for most classes, there's one class that this achievement is exceedingly easy for: the Sniper. If your nemesis is a Sniper, simply sneak up on him and smash him with your shovel until he drops dead. It's as easy as that! As for any other class, you'll need to watch until they have been weakened before you can kill them with your shovel.
Farming this achievement is tedious because there are no other achievements it can really be farmed with, except possibly Wings of Glory. have a friend damage himself so that you can kill him with a shovel. Have him kill you three times so that he is your nemesis. Then kill him to get revenge and the achievement. It's easy, but lacks connection to the rest of the achievements, which is annoying.
Note: When this achievement says that you are killing your nemesis with a shovel, you are actually killing him with an entrenching tool, not a shovel. The difference? An entrenching tool is a sort of cross betwenn a shovel and a spade, and is collapsible. A shovel has a much flatter blade, and is normally not collapsible.
Destroy 10 sticky bombs with the shotgun in a single life.
You only have one method of destroy stickies. It's not your rocket launcher and it's not your shovel. Rather, it's your shotgun. It's actually quite easy to destroy stickies with your shotgun. Simply point so that your crosshair is on the sticky and shoot. If the center pellet hits the sticky, it will get destroyed. To get this achievement, simply stay alive while you clear out some bombs with your shotgun. This is easiest if you have a Medic backing you up and the Demoman is planting stickies within easily-reaching spots for you to shoot.
To farm this achievement, get a friend to play as the Demoman and plant a bunch of stickies. Then shoot them with your shotgun. Do this until you accumulate 10 in a single life, and you now have the achievement. Simple as that. If you want, you can go on to kill your Demomand friend for credit towards the Demoman kill grinding achievement (Out, Damned Scot!)
Where Eagles Dare
Get the highest possible rocket jump using jump and crouch.
There's no point in separating farming and doing this achievement normally. To do it, you must have mastered the technique of uber rocket jumping. This is achieved by crouching, jumping, firing a rocket, then releasing crouch right as you are hit. The upwards momentum created by you standing up will give you a good 25-50% more jump velocity, enabling you to travel farther or higher than doing a normal rocket jump. Naturally, you have to do this achievement outside, as it will not count inside. It's the easiest achievement to get in this entire pack, assuming you know how to do it right. You can also get it by performing a grenade taunt while overhealed, which will launch you instead of kill you.
Note: The Soldier apparently loves his World War 2 movies. Where Eagles Dare is one of Clint Eastwood's better movies. It involves the infiltration of a German-controlled castle. The movie is full of twists and is a classic of the spy thriller genre, and for those that haven't seen it, you should. It's one of the best action thriller movies around.