First, consider race. Like many other decisions, you'll need to use your imagination here. My first thought was, I'm an Imperial - they're my go-to race in most games, probably because they seem the most 'normal' and all-around average of the options. But then I thought about their stats and powers. Am I really all that convincing or persuasive (Voice of the Emperor, high Personality, Speechcraft & Mercantile)? Do I get energy from other people (Star of the West's Absorb Fatigue)? Nope.
Conversely, my wife thought she'd be a Breton. She always loves playing Bretons, has since Morrowind. But the Imperial skillset and stats fit her better, she realized. And the Breton made more sense for me (the Prima guide describes them as "conservative, defensive", which is basically me, and their magical focus suits me better if I picture it as an interest in theology and metaphysics ).
Next, Birthsign. I went with Apprentice. I figure Magicka would best translate in our world to an interest in esoteric knowledge, or discipline, which I have - and the Weakness aspect seems to fit my various quirks and sensitivities.
Combat, Magic, or Stealth specialization? Combat works for those who know how to fight, or are actively athletic, or maybe know how to repair things (Armorer). Magic would be for academic types, maybe those of philosophical or spiritual bent. Stealth is for agile folks or those with good social skills.
Pick your 2 favored attributes out of Strength, Endurance, Speed, Agility, Intelligence, Willpower, Personality and Luck. Which 2 of these attributes do you exhibit the most?
Now the fun part - major skills! Pick your 7.
Combat skills seem straightforward. Most people probably don't have a lot of experience with actual swords as weapons, but if you've practiced sparring you might take Blade.
Stealth skills are similarly straightforward. Acrobatics for those who are acrobatic; Sneak for those who are stealthy. Marksman can work if you are good with a bow - or a gun (though gun skill might also represent Destruction, since aiming is important!).
Of course when it comes to the magic skills, you're not measuring your ability to toss fireballs around literally. But... do you like fire? Do you enjoy playing with electricity? Maybe Destruction is your thing. Are you really persuasive? Sounds like Illusion. Alteration can be represented by a sound knowledge of the workings of the physical world - do you like science? Do you like to figure out how things function? Conjuration is a bit tougher - but my wife took it on the grounds that she had given birth to our kids . Alchemy makes sense for people who do a lot of cooking or know a bit about plants and herbs. Mysticism could represent someone with a strong philosophical bent, always wondering about the big questions of existence. Restoration could have to do with inner discipline or stability, or an ability to actually heal.
So here's what I came up with after a few minutes:
Race: Breton
Birthsign: The Apprentice
Specialization: Magic
Favored Attributes: Intelligence, Willpower
Major Skills:
Marksman
Speechcraft
Sneak
Blunt
Athletics
Mysticism
Restoration
I have experience shooting bows, so Marksman is obvious, and I teach for a living, so Speechcraft makes some sense too. I can be fairly quiet at times, which explains Sneak - but also the fact that Sneak also represents the perception of NPCs, and I'm decent at spotting and listening. Blunt because I would probably be more comfortable swinging around an axe than a longsword, if need be (though I'd definitely prefer to stay out of melee combat - hence, to some extent, the Athletics! Also, Athletics fits since I do run occasionally and I'm not totally out of shape - yet). Mysticism and Restoration since I love thinking about infinity, existence, God, etc.
Character sheet in hand, I went to the UESP to find out a class - player or NPC - that resembled what I had. Nothing did, and I was again reminded at the sheer amount of possibilities available in this game. What would you call such a strange mishmash, though?
It's an odd bunch of skills, though, and I can't help but wonder how they'd play in Oblivion. Seems like a sort of sneaky Pilgrim, but with magic. No armor skill means he'd rarely get into melee range to work up his Blunt; Marksman and Sneak would be doing most of the heavy lifting, with Speechcraft to ensure that most fights are avoided (if only that were possible in Oblivion). The Mysticism skill has a lot of utility that would come in handy defensively; ditto Restoration.
Anyway, it's a fun thought experiment, and once I'm done with my current Acrobat I may take this digital 'me' for a spin in Cyrodiil. Sure, it's a little solipsistic, but I'm really eager to see if I can pull off the playstyle - even if it degenerates into basically running from city to city and avoiding dungeons like the plague!
I just need to think up a name for the class...