Easiest is probably elf or half-elf male with sold your soul background.
Best is gnome male with only child background.
Difference is higher Magic Aptitude at start on the first one, which makes combat easy the whole way. MA determines how much damage your spells do.
The 2nd one is much better overall because it is willpower heavy instead of MA heavy. You gain MA from learning spells as you level up anyway, and you will almost undoubtedly max it at 100 regardless of what type of mage you make, which is why it's better overall to go for willpower at creation on a mage.
At creation, put 2 points into the melee skill (get dex if you have to), 1 point into persuasion, get the minor healing spell, and put the last point into dex.
Now get harm (necro evil level 1 spell) as your first damage spell. Next spells you should go for are fireflash (level 3 fire) and stun (level 2 mental). You can win the game with just these 3 spells.
Other good spells to have are unlocking cantrip (to unlock chests), agility of fire (for dex), all of the temporal spells. Optional are teleportation and conjure spirit (if you want to kill important people but still progress through the storyline). You'll want to get unlock and agi of fire real early since they are only level 1 spells but really useful.
As far as stats go, you need to start out with the 2 into melee and 1 point into persuasion and some type of healing, which is what I recommended. If your character can't get that with just 5 points at the start (low dex or charisma), spend the level 2 or 3 character points to get there.
After that beginning stuff is covered, you need to get the spells I recommended, and get the willpower to be able to get them as necessary. After you got the spells you want/need, max out dex first and str second and just roll through everything. You can completely ignore con, bea, int, and chr if you like. You should know that int lets you get more maintained spells (5 at 20 int) and charisma lets you get more followers in your party (20 at 5).
I should note once you really get comfortable as a mage with the spells you need, you should increase your melee and dodge skills and put on nice equipment to fight as well as cast.
More info from: http://www.gamefaqs.com/pc/914155-arcanum-of-steamworks-and-magick-obscura/faqs/63974
NOTES ON SPELLS:
Casting spells reduces fatigue.
If you don't have enough fatigue to cast a spell, but try to anyway, it will
fail and you will fall unconscious.
You must have an INT of 5 to learn any spells.
Spells have a level requirement, listed on the character stats screen spells
section (where you learn them).
The level required for the spells of each school are always: 1,1,5,10,15.
Order is 1st spell to 5th spell, so at 15 you can learn any spell.
Line of sight is required for many targeting spells.
Casting a spell on a technical target will increase your chance of failure.
Fireflash will hurt enemy armor and can break open chests, doors etc.
Spells have a level requirement, listed on the character stats display spells
section where you learn them.
The level required for the spells of each school are always: 1,1,5,10,15
damage can be reduced by enemy resistances of course
harm - single target, long range dmg. DMG = 5+(MA/3)
fireflash - aoe dmg, doesnt hurt allies, will hurt enemy armor. Also useful
for destroying locked chests and doors. DMG = 12+(MA/5)
disintegrate - extreme damage in the thousands but costs 50 fatigue and
destroys corpses and items! Not always helpful or efficient.
you won't need more combat spells than these. Fireflash and minor healing
alone can get you through the game.
agility of fire - raises agility by 4 (can affect same target multiple
strength of earth - raises strength by 4 (can affect same target multiple
shield of protection - raises damage resistance by 25+(MA/5)
hasten - doubles speed (best applied after tempus fugit)
tempus fugit (final time spell) - slows enemies, increases you and allies
speed by 10
conjure spirit (talk to people you've killed)
SCROLL OF EXITING - WARPS YOU TO BEGINNING OF DUNGEON OR AREA! WORTH EVERY
PENNY! Only available in scroll form from shops. You should always keep 2 of
these in your inventory once you can afford it.
GOOD EARLY MAGIC:
good early available magic gloves - Gloves of Dexterity DEX+2 from Ashbury
good early available magic ring - Poison ring from Forgotten Pit east of
good early available magic boots - Enchanted War Boots +5 Speed from magic
smith in Tarant
good early available magic sword - Sword of Baltar from pickpocketing/killing
Lelliana in Durnholm
good early available magic robes - Silent robes found on the magic item shop
merchant in Blackroot
MAGIC APTITUDE AND TECH APTITUDE EXPLAINED:
Useful Magic and Tech items which seem to ignore aptitude:
tech mixtures and medicines (like fatigue restorer, etc.)
scroll of exiting
Magic aptitude (MA) and tech aptitude (TA) are kind of like an alignment
range except for magic vs tech instead of good vs evil. When you press C to
go to your character stats, the rightmost horizontal meter that says Magick
Tech Meter when you hover the mouse over it displays your rating. The number
above and below it is what we are concerned with (top is magic, bottom number
is tech). Think of the top as a positive number and the bottom as a negative
number, for simplification. Negative means how technical you are, on a scale
of -100 most technical (shown as 100 on the bottom) to 0 neutral. Positive
signifies how magical you are, with 0 being neutral and 100 being most
magical. This affects how tech and magic affect you, ESPECIALLY ITEMS AND
SPELLS. Spells will fail on highly technical targets.
MA is increased by learning spells and wearing some items, TA is increased by
learning tech skills (firearms, lockpicking, etc) and learning tech
disciplines (explosives, electrical, etc.). That which increases MA,
decreases TA, and vice versa.
Tech items are almost always influenced only from 0 to a positive range, but
magical items are influenced from a negative range to a positive range
(ranges determined by item). So, neutral 0 allows 50% magic benefit from most
magic items, and 100% benefit from tech items. 100 allows little or no
benefit from tech items, and 100% benefit from magic items. -100 allows
little or no benefit from magic items, but 100% benefit from tech items.
SCROLLS AND POTIONS ARE MAGIC- so your aptitude WILL affect failure chance of
these items, which can be critical when you're trying to drink a potion of
health in combat to avoid death. Tech users should buy healing mixtures from
herbalist shops, or craft your own.
Spell effects usually increase as magic aptitude increase, but some have
certain caps, while others will benefit as long as aptitude increases (even
if you push MA over 100 and it only lists 100 on the character stat screen).
Charged rings have an unlisted required tech aptitude to receive the full +2
DEX. The requirement is 13 TA or more.
High MA prevents the use of trains or subway systems.
Skills require a stat be at a certain number before you can increase it
further. The requirements are:6,9,12,15,18. The stat differs between
Skills are maxed when you spend 5 character points into them, so they are
divided into 5 'ranks'. Differences can happen due to ability stat effects,
item bonuses or penalties, racial or background inherent bonuses or
penalties, and so on. But all of these lesser effects on a skill are almost
never equal to one full character point spent towards that skill.
Weapon skills (melee, throw, firearms, bow) main purpose is increasing the
chance to hit an enemy using that type of weapon, and it is painful to try
without a high rank in the skill.
You should focus on one weapon skill and use that type of weapon through the
game, so as not to waste character points.
It's a good idea to increase your weapon skill (melee, most likely) very
quickly and very early, or it can take forever just to hit your enemies
enough. Getting 4 ranks into your weapon skill is usually one of the top
priorities for a hero. Mages can get by with spells, if you prefer (but even
mages with some melee makes otherwise frustrating fights much easier).
Pretty much everyone benefits from dodge.
Skill training is separate from skill rank. Skill training level is written
next to skill name in parenthesis on the character stats screen, and is blank
Skill training provides certain extra related benefits and is purchased by
asking someone who can train you. Basic training can be found all over,
especially from city guards, but only certain people can provide expert and
mastery. You need at least some of the skill ranked to receive basic
training, and you need about over half to receive expert. Master training
will probably be refused unless the skill is fully ranked (red bar fully
across the skill in character stats screen) and usually involves a quest.