I just copied a previous post I made regarding skills for a thief as opposed to re-writing it:
Ok, first thing to note, you can get by with just 100 stealth fine. I would suggest trying to get the Shadow Dancer Leggings, they add +20 stealing and Stealth.
Burglars Bandanna will add +10 stealing which can be blessed with a clothing bless deed.
I suggest keeping stealth at 80 and just use the leggings to get to 100
Stealing at 100 and use the leggings to get to 120.
Resist is fine, I have GM resist on my thief, it helps to resist poison and paralyze (without the use of omen of course). It might help a bit when running away. Of course, you don't need resist.
For Ninja, I would just suggest getting it to a level where you can cast shadow jump and leave it there, unless you want the better selection in animal form. I have mine at around 80 or so since all I needed was llama form and shadow jump.
Now for spellweaving. I did the quest on my thief so I could use some of the spells, and left it at 0. I can cast the healing spell and the armor spell.
Chivalry: since my template doesn't max out some of the skills, I was left over with around 30-40 or so skill points. I decided to add those points into chivalry, and I did this for a number of reasons. It let me cast heal, cure, that one spell that restores stam, and divine journey (recall). Nice thing is that you don't need LRC or and regs, all you need is to donate gold to shrines to be able to cast them. If you loot the left over gold from spawns, gold is no issue
Don't bother with lockpicking though, nothing to be gained in chests at this moment in game play.