WIS > INT > (CHA > DEX) > (CON > STR)
My reasoning: WIS is the most important dialogue check. INT is important for some dialogue and important if you are a wizard (you will be…). CHA is not as important if you already have WIS, and most CHA checks can be skipped with WIS. DEX is interchangeable with CHA in position. Get it to IIRC 13 so that you can grab people. STR I never cared for because I was a wizard, and they are better and more interesting than fighters. Also my main incentive for STR is gone: in most games it affects your carrying capacity. A good point on CON is made above, but I don’t use it because, well you’re immortal. If you die, hop back up again and kill the enemies some more. If you’re a wizard, you shouldn’t even be in the front lines, make Morte taunt them.
So I always max wisdom at the beginning (18?), INT goes pretty high (16+?), CHA and DEX to 13, and STR stays 10, anything else can be CON.
Alignment: ideally, it is best to be Lawful Good. There are 2 +CON items that only a LG person can use, and a weapon that is LG only. However, you may wish to stay LG until you increase your CON, then switch to something else. Although I found it difficult in this game to NOT be Chaotic. It makes for a funnier experience.
Not a spoiler because it happens so early I think, but before you leave the first zone, make sure you find Deionarra and that she teaches you something very useful (may require minimum stat levels).
Also, if you don’t mind cheating a little, there is a patch that gives you the max HP bonus each level. I say a little bit of cheating because I imagine many people would alternatively save scum instead, and this just takes out the grunt work.