Here is my guide for introducing new players to the game. This guide is meant for experienced captains who find themselves with one or more new payers who need to be shown the ropes. Full disclosure: I don't always follow my own advice. I get angry at new people, I curse, and I am probably responsible for some bad first time experiences that have driven people away from the game.
If you are introducing a friend, have him/her join you in a practice game where you can introduce them to your ship layout and let them fire as many practice rounds with the various guns to get used to ship momentum and shot drop. Also use this time to explain the difference between rebuilding and repairing.
If you get a rookie addition to your crew and want to bring them up to speed I suggest assigning them to the balloon/gunginner on a pyramidion (preferably with a chain gun mount). This position allows the new player to get familiar with the repairing and shooting mechanics without putting the ship in danger by taking up a critical roll (only gunner or hull engineer). Sometimes you will need to show the new player where the ladder is. I like jumping up an down to get his attention, then tell him to follow me as I walk up the ladder and park him at his new gun. In general when teaching a player a new ship stick them on the gungineer roll as it will let them experience the fun of shooting things while having the tools to fix their own gun when things go bad.
Since your new crew member isn't familiar with the information being thrust in his face the captain should keep an eye on them and provide pointers should they miss something important. Stuff like:
Shoot at the ship with the white box around it.
Hold your fire that one is friendly
Your spray is too wide, use heavy clip to tighten it up.
Your gun is damaged hit it with the mallet and it will turn faster.
Adjust your aim (up/down/left/right) to compensate for shot drop, ship momentum, or target movement.
The balloon is on fire get off your gun and put it out.
New target, <player Name> look <up/down> and <left/right>.
Switch to <left/right/forward/rear> gun, target <high/low/left/right/front/rear/very close/at range>.
When the new player successfully complies with your instruction provide positive feed back by thanking them. If they fail to comply repeat the instruction. There are (were) bugs in the mic chat where some players could not hear the captain, before getting mad at an unresponsive crew member check that they can hear you with text chat. If you can't spare the time to type ask one of your responsive crewmen to relay the message in text chat. Also be aware that some players don't speak English or don't know it that well. Try not to get mad at them for reasons beyond your or their control.
If anger is unavoidable try using emotional blackmail instead of cussing. Let them know that they are letting down the entire crew. Let them know what action they preformed/failed to perform led to the ship's demise. Also be honest with your own mistakes. If you left the Helium on for too long, drove into a dust cloud, or charged into a bad situation; own up to it. Letting the new player know that a failure was not their fault will keep them playing when your team gets stomped 5-0.
Accept defeat gracefully, if a rookie or three join your crew mid game, you are going to loose and there is nothing you can do about it. This is especially true if they join as the wrong class. Explain your situation to the other captains over Captain chat, let them know you can't be as effective as you would like. Also use the time productively start setting up your strategy for the next game. Let the new guys know what class they should select and what equipment they should bring. Give them the run down on how the guns and engineer items work. If the game is still dragging on after you get your crew ready for the next game suicide rush the enemy team to get it over with quickly.
Below are some class specific advice I give new players:
First time Engineer Spiel:
There are three things an engineer needs to do: repair, rebuild, and put our fires. Repair is needed when a component has a yellow circle above it, and is best accomplished with the mallet. Rebuild is needed when a component has a red circle above it and is best accomplished with the spanner (small wrench). Fire and fire extinguisher you should be able to figure out. When a component is red click on it with the spanner on it as fast as you can. When a component is yellow hit it once with the mallet and you will see a clock wise countdown. Hitting it again during that countdown does nothing, so you should go hit other things with the mallet in the mean time.
First time Gunner Spiel:
Let me show you to your gun...
At this range ammo type **** is the best
The ship's momentum transfers to your bullet aim left/right to compensate.
When I say "**** side guns," I want you on this gun...
Don't worry about repairs, *engineer name* knows what they are doing.
First time Pilot Spiel:
It is a good idea to learn the other two rolls before you try flying.
Your gunners will have an easier time hitting targets if you are at neutral throttle.
Just keep the dangerous end pointed at the enemy.
Reverse is perfectly valid throttle setting, you don't have to turn around to go the other direction.
We can't hit effectively at this range. I suggest you drive us closer.
You turn faster when you are not flying full speed ahead.
Turn left/right or go up/down your gunner's don't have a shot yet.
Don't worry my first time piloting was worse *insert horror story involving your team getting stomped in under 5 minutes*