What extra 0-level skills would you give to characters at the start of a game?
I'm thinking things like Computers-0 or Imperial Culture-0 or even Spacer Knowledge-0. Things that should be mandatory, just for being trained by the Imperium or an Interstellar MegaCorp or such - like something everyone except a Barbarian should have. Or like something a new player wouldn't think of to ask about if they could make an EDU roll for it.
In CT, there are a lot of skills that a character can use with Level-0 or no skill at all, with no penalty.
Note that there is no general penalty for not having a skill level in a skill. The penalty is usually task (and Ref) dependent, where a character might get a penalty for not having a skill on one task but be able to roll without penalty on the same skill for a different type of task.
Characters created with Book 1 are given all the weapon skills in that book at Level-0 (this does not hold true for characters created using Supplement 4).
The Traveller Book says that are appropriate for level-0 are air/raft, ATV, forward observer, steward, vacc suit, and weapons (which, as I just noted, the book gives to characters created using The Traveller Book).
As a Ref, I am likely to give a character a Level-0 skill if his background makes for a good case that the character has the skill.
And, I am most likely to allow Level-0 skills with skills that don't formally mention penalties for not having the skill in the skill descriptions.
For example, if a character is from a waterworld, then I will probably agree to allow the character to have one of the Watercraft skills at Level-0.
Classic Traveller skills are divided into three groups: Basic Skills, Weapon Skills, and Transport skills.
The character, if generated with Book 1/The Traveller Book/Starter Traveller, gets all the listed Weapon skills at level-0 by default.
With the transport skills, I would make a determination on that based on the character's background and homeworld. Where did he spend his time during character generation? Did he use transport skills a lot during that time?
With Basic Skills, I would be harder on these. These are the skills that a character should earn through character generation. I might include them on the character's skill tables (replacing a skill from the default skill table) with a Basic Skill the player wants--I am more likely to do that than to just give a character a Basic Skill at level-0.
Next, I'd read the skill description. If it mentions a penalty, then I am less likely to award that skill as a Level-0 skill.