It's hard to win a game if you don't even know the rules.
If you don't learn how to cast spells you won't get far.
Very important is the character creation, you'll suffer from mistakes you make there until the end of the game.
You probably already found out that you can reroll until you get a high sum of stats and transfer points from unimportant to important stats afterwards.
A character with 14 in all stats is horrible since 14 usually isn't better than 8, 18s make the difference.
Most important is that all your party members start with maxed out dexterity, the +4 AC bonus for 18 dex will make sure that you're hit far less often and the ranged attack bonus isn't bad either.
Con and str are important for everyone too.
Only mages and bards benefit from int, only clerics and druids benefit from wis. Cha is useless except for one character who does the shopping and talking.