Generally, when I play the elder scrolls games I tend to end up focusing on about 4 skills, just because of my playstyle. For example, in Oblivion, my orcish warrior was a master of heavy armor, blunt weapons, and repairing things. My Breton mage mastered conjuration and destruction before anything else, and was quite experienced with alchemy and restoration
Think about the skills you'll be using to solve problems in game. Those are what it should come down to, really. Everything else can be dabbled in