[Ravager]

For tag skills, you're stuck with 3.
Choose them well though, once you start putting 100+ points in them, they're incredibly useful. Personally I always go for a weapon skill (usually One-Handed Melee and/or Ranged) and Fortitude (for healing - much better than simply relying on potions). The third skill I change over, sometimes Open Locks, sometimes Speech or Find Traps. It depends on what kind of character I'm going for.

Traits are optional IIRC and I don't normally go for more than 1 of them, I don't like the disadvantage too much.

But now I think Gifted is better than S.Tinkerer because it puts all your attributes up one point which is worth it even though you lose 4 skill points on levelling.

I'm always looking for more skill points on a level (through the Perks + Belt & Necklace of Voodoo combination), the more skill points per level you get at the beginning the better the character will be at the end. So when you see any Perks offering extra skill points I'd generally go for those.
I don't normally go for other spells, I've tried them (particularly the Necromancy spells which were useful) but I prefer melee.

I've tried all the races and all the races with different Spirits - but they all seem to fail as you get past Montaillu. Maybe I'm just doing the order wrong? I go from Montaillu to the Crypt, and the Crypt kills my char every single time. I'm thinking of going to wherever it is the Rock Titans have enslaved the citizens instead.

The spirits are effectively pointless, they only offer 1 point in each spell branch they focus on (e.g. Divine Spirit puts a point in each of the Divine spell branches- something that you could gain easily enough on your own).
I remember having great difficulties with the Brimstone Soul Reavers on the first time through the Crypt. Hitting them was very hard. The best solution is just to pile points into whatever weapon type you are using. That way you should be able to hit creatures easier (and keep doing it as enemies DO get a lot harder). The Crypt was probably my favourite area in the game though, with lots of treasure dotted around. One item can be found behind a secret door called the Ivory Mace of Divinity that does extra damage and has the chance of annihilating an undead foe. That helps especially with the regenerating Revanants you will find.

Also I'd recommend continually going back to the merchants, for me, they seemed to have new items every time I levelled up. Especially Alvarez, the merchant at the Crossroads.
One way of getting good experience is to take advantage of the random Crystal encounters. Clicking on a blue crystal that transports you somewhere sometimes deposits you in an Etheral area which can have Goblins, undead, Hujark etc. dependent on level. These areas ALWAYS seem to have some hidden treasure to find. Good quality treasure too.
Just keep clicking on the crystals and you'll either be transported to the random area or shown the map- if you're shown the map, exit it and click on the crystal again. Keep doing it until you do get the random encounter.
Look out for items that increase stats and resistances, I always kept the best elemental resistance shield and weapons that improved skills like Find Hidden Doors (and sometimes just bought them so they could be used for those specific occasions).

I think that's all I can offer for now.
If you have any questions, feel free to ask, I'll try and remember more stuff if you need it.
Sorry that's such a long post, it's probably my longest ever.
Hopefully you'll be able to follow what I've written.