I get the impression from things I've read on the Web, and some conversation with other gamers I know, that big long skill lists have had the unfortunate effect of unconsciously convincing players that their PCs can only do things that have a defined skill on their character sheet. The well-known essay Quick Primer on Old-School Gaming explains this well. It's worth reading. When I referee, especially for my kids, I want them to experiment, to try creative solutions to problems, and experience the fun when something they thought up succeeds.
To allow characters the freedom to try lots of things, and to not run afoul of this balancing rule, I rely on characteristic-based task resolution. Skills to me are the things that you have to be trained in to do competently (think of the NPC-only no weapon skill penalty) but there are plenty of activities that anyone might try to do that aren't covered by CT's brief skill list.
My guiding principle is this : Whenever possible, associate tasks with existing skills & characteristics instead of requiring new skills.
Lock picking is a reasonably common thing for PCs to try, and while a defined skill in lock picking is very plausible, it eats into a PC's skill limit, and can only be applied to one very specific activity. Better, I say, is to associate that activity with Mechanical or Electronics skill, depending on the lock's TL. Lots of PC's have this skill already, and it allows the PCs to try something 'off-book' without encumbrance.
If there isn't a skill (there's always J-o-T) that makes sense to associate with an activity, then the referee can associate it with a characteristic. I like the EDU stat a lot. Maybe because in real life, I'm a college librarian and I deal with academic books all day, and I just like learning new stuff. Whatever the reason, I see EDU as being key to all kinds of activities in Traveller that aren't covered by the rules. If it's scholarly at all, EDU covers it. History, geography, the sciences, literature, art; any time these topics come into play, ask yourself: how well educated is my PC?
Referees can just decide on a target number, and what characteristic value would provide a DM; that is the CT skill system in one sentence.
Dexterity: Catching things, balancing, jumping across, escaping bonds
Endurance: Resisting environmental stresses, running long distances, resisting collision damage, staying awake
Intelligence: Puzzle solving, figuring out unfamiliar technology, attempting unskilled technical skills, cryptography
Education : Knowing facts or information, current events knowledge, general research or science, general history, appraising value, technical bluffing
Social Standing: Recognizing famous or important people, acting correctly in a foreign culture setting, knowing the local laws, savoir-faire at social events
Technical Intuition ([INT+EDU]/2) Used as a form of investigative skill. Determining 'what happened' based on physical data, what a device does apart from observing it in operation, and judging general technological achievements.
Intimidation ([STR+SOC]/2) “leaning on people” to get cooperation.
Social Bluffing ([SOC+INT]/2) Social bluffing can get you into a private party, convince someone you are someone that you're not, or get you in to see the CEO without an appointment.