Easy "Well Done" Achievement
To get this achievement you have to knock yourself out with a wrench you threw.
Step 1: Get a wrench and equip it.
Step 2: Stand next to a wall and press T. This will open the throwing mode.
Step 3: Aim it directly at the wall, so that the wrench will reflect right back at you.
Step 4: Throw the wrench.
Tips
Read every tooltip! Heat Signature tells you almost everything ingame, and what it doesn't explicitly tell you can be inferred based on what it does tell you.
Hold F to speed up time by 6x. Immensely useful when you're waiting for a guard to leave their group or when approaching a ship.
Destroyed rooms act as impromptu airlocks. However, since there's no door between your pod and the ship, enemies can see you through the forcefield.
You can attack random ships by just flying around. Ships will usually be specific to the faction whose space you are in, and will always have a time limit (since they are always heading to a station). Useful for gearing up from crates before attempting more difficult missions.
Guard corpses can be used to prop open doors. Useful for using Sidewinders.
Thrown objects cause noises when they hit walls. Useful for attracting guard attention without using guns. Be warned: guns will go off if thrown against a wall!
Guards are not alerted by your unconscious body. This one is a little ridiculous, actually. If a guard spots you, as long as you knock yourself out before they shout intruder, the alarm won't sound. You can use this to your advantage to prevent an otherwise missionending alarm.
Subverters will remove the lock from a key door. Subverter grenades are especially useful if multiple key doors are next to each other.
You can permanently advance through sections by using Visitors twice or more in a row. The most recent start location will be your final return location, so with enough Visitors you can effectively teleport the entire length of a ship.
All guards will die if spaced. If you can lure a guard to a room and then cause a breach (shoot out the window or blow the room), if won't matter if they are shielded or armored.
You do not have to complete a mission to recharge items. As long as the ship doesn't have a time limit, you're welcome to go to a station and return.
Keys of a higher number work on that number lock and below. Since key cloners usually have limited uses, you should seek ouy keys which are one or two higher than your current section.
You can grab enemies the moment you harm them with a melee attack. Useful to keep them from flying into another guard's vision.