Your class trainer can reset your soul points in a particular role for a small fee (think this is level dependant) but at 17 its about 3 gold which is pennies really.
Regarding builds, it's quite hazy.. people have made some public after finding their effectiveness, spotted a good warlock/elemantalist/archmage one for high end pvp that focuses on survivability against burst damage and self healing but tbh the important thing is to keep switching. i constantly analyse my play, what i'm using, what i'm using it for, do i need higher armour? Shall i drop these heals and concentrate on more damage, screw this buff i'd rather have x.. that sort of thing. And the beauty of the game is that you can do this all day, everyday for many months and you'll always have compensations for every choice you make.
I love this as it completely voids any "I can beat everything except clerics" "i never run out of mana" "certain class is OP" because there is no class system really. Unless after a long testing time in pvp for example you could fin out that you can beat Rogues with 17 Assassin/14 Sab /5 Ranger builds. The glory in that is you wont come across that particular build nearly as often as you would in say "I don't have a chance against resto druids in wow"
Everything can be beat, some soul vs soul combonations will have tricks and abilities more suited to dealing with others but the huge variety of points just means you switch role and that opponent is nowhere near as challenging anymore.
Also i can recommend grabbing good skills, i've gone outfitting/butchery and runecrafting so i make my own armour, supe it up with planar bonuses, then runes.. its like every 3 or 4 levels you twink yourself to the best you can be at that level, love that.