I’ve been a noob even after ~100 hours, no worries.
Just look at skills stats and how they scale. By checking skill stats per level, you’ll know when you want to keep on adding a particular skill or stop. It should not really depend on how everyone does a build, but how you want to do it. For example, Soldier’s Cadence has 420% Weapon Damage at level 16/16, and 500% at level 26/16. Many people would go for it, and I, for example, don’t go for it if I need more points to spend somewhere else. Also, the 80% Weapon Damage is not a big deal to me, but other people can call me stupid for not over-maxing it.
So basically, just think about what character you want, then look at all skills in a class and check what they do and how they scale. You might find a skill super cool, then try it out in game and realize it’s trash, but you also can think the opposite, where a skill is trash but it ends up being super strong.
Not every skill scales in a superior way; some skills are way more worth leaving at level 1 or just used as a devotion proccing skill. Also, some skills get great bonuses from gear, and even if you think the skill is trash or isn’t that great (for example soldier’s Decorated Soldier skill) you still might want to lose one point on it to have the 8/8 bonus because your gear gives you +7 to it or even +10.
If you learn how to manage your skills, you’ll learn how to build your character in general. You’ll look at the game differently, and seeing a skill like Forcewave and knowing its functionality will make you think about building over that particular skill and you’ll look for items that boost that skill in a solid way.
The most important rule in character building is Resistance Reduction, which allows you to deal massive damage, otherwise you might either deal very little damage or no damage at all. So basically, if you want to focus on a particular damage type, you’ll have to search for at least one mastery that shreds the defences of this particular type. An example might be physical soldier build, you already have some RR in the War Cry upgrade and you can take Occultist mastery for another, stackable RR.
I am generally very bad at explaining things, so I hope I didn’t mess your head out. 