Game Skill

Be Inspired
I like to see players exercise their imagination during a game, even a board or card game, as evidenced by the way they describe how they see the action in their mind's eye. I enjoy creative thinking on their part, adopting a clever approach to problems. This is a chief source of entertainment for me whether I am playing a character or refereeing. I like to be surprised by something I didn't think of. Of course as a player I also enjoy seeing a plan I have contributed to come together nicely and succeed. Sometimes it can be entertaining to watch our best laid plans unravel before our mind's eye and then be faced with in-game disaster. That's challenging!
In White Box you roll six ability scores and that's a game character, a playing piece, an alter ego, a role and your ticket into the game. Six ability scores, Strength, Intelligence, Wisdom, Constitution, Dexterity and Charisma. The first three abilities can be Prime Requisite scores for Fighting Men, Magic Users and Clerics, respectively. High scores in those abilities grant an increase in earned experience. Constitution can add 1 to each hit die for Hit Points, and Dexterity can add 1 To Hit with missiles. Otherwise five of the six ability scores play no further part in the rules as written. The exception is Charisma. Scores in this ability determine the number of hirelings a character may employ and how loyal those hirelings are likely to be. Charisma is mentioned as playing a part in the reaction of monsters and NPCs. No mechanics for how this may work is given in White Box. This is where creativity comes into play.
I see the ability scores as an invitation to imagine. Imagine what they mean for your character. Imagine what you can do with them in the game. How could Dexterity be used to solve a problem? Charisma (low, average or high) begs to be role-played. What is the difference between Wisdom and Intelligence? How do we role-play that? The six ability scores give the imaginative player a lot to work with.
Many referees add additional "house rules" to adjudicate in game questions of whether a PC can succeed in a given action. The question, "What do you want your character to do?" often results in a die roll to determine success or failure. White Box is a game of referee rulings. Outside of To Hit rolls and Saving Throws exactly how questions of outcome are to be answered is mostly left to the referee. That doesn't mean players should never suggest a way to handle something at the table. As referee I eagerly entertain a player suggesting his high Dexterity might be useful in a described way.

Vol. I: Men & Magic lists the following:

RECOMMENDED EQUIPMENT:
Dungeons & Dragons (you have it!)
Dice — The following different kinds of dice:
1 pair 4-sided dice 1 pair 20-sided dice
1 pair 8-sided dice 1 pair 12-sided dice
4 to 20 pairs 6-sided dice
Chainmail miniature rules, latest edition
1 3-Ring Notebook (referee and each player)
Graph Paper (6 lines per inch is best)
Sheet Protectors (heaviest possible)
3-Ring Lined Paper
Drafting Equipment and Colored Pencils
Scratch Paper and Pencils
Imagination
1 Patient Referee
Players

Note - Imagination and 1 Patient Referee!  As Matt Finch says, "Imagine the hell out of it!" Imagination is perhaps the single most important skill in White Box. Being able to imagine the situation described by the referee and being able to come up with an idea to address the proposed challenge (again as described by the referee) is essential to both enjoying the game and successful play. Thinking creatively, often outside the box, bargaining, retreating to regroup, experimenting, and occasionally rolling up a new character so you can jump back into the game and try something different are essential skills. Never forget the game is being run by a real person who can clarify, answer questions, with whom you can negotiate, and even ask for help.
Skill as a player is often as simple as developing social skills. The ability to make joint decisions, work together and benefit from the strengths of each team member are useful skills in our hobby. Pay attention, especially to details and voice inflections as the referee role-plays the NPCs. The referee will often give important clues in the form of small details mixed in with a longer description or use their voice to suggest sincerity, deception, fear or other emotions being role-played. Paying attention to details and occasionally taking notes can be very helpful. Talk to the NPCs, they may have helpful information.  Making a few friends among the NPCs can be very helpful in campaign play. Creative use of seemingly mundane objects, either found in the dungeon or purchased prior to the delve, can often save the party from much grief. A ladder makes a nice bridge in a pinch. That lamp oil is slippery in addition to being flammable. Food is a universal language. Monsters that may prove too perilous to fight can perhaps be bargained with, or tricked. Luring the big baddie away from its lair so the party can steal its treasure gains almost as many experience points as killing it and then looting its treasure. When all else fails and you are looking at a total party kill (TPK), try bargaining, offer ransom for your PC's miserable lives. An entertained referee is a cooperative referee.