This is something that does largely come with experience. My first character in DS1 was so unbelievably gimped but I didn't know it until I did a bit of research and started focusing stats.
A lot of builds are designed around the weapon you are using so a first play through is often a bit of a stab in the dark.
If you are going a str hero then I usually get my str up to the weapon requirement, then start boosting endurance then work on vitality and vigor last. Str so you can use the weapon, endurance so you don't run out of stamina using it and then the other 2 to make you tanky. Spreading your points thin between them early can often end up making you wait till end game to use the weapon you want to use so best to get the required stats up first if you've found a nice weapon you want to try.
Then also take a look at the stats scaling and see if it's worth going above the requirements if the scaling is good. Especially by the looks of it if you go heavy infusion which boosts strength scaling.
Generally the best base stats for a strength build end game tend to be:
40-50 str
30-40 end
30-40 vigor
Whatever vitality feels right. Though usually you can find a ring which enables you to wear heavier equipment (supposedly there's over 100 rings in game so there must be one for this).
And then whatever other base stats you need for a weapon e.g. 16 dex or something.
Mind you this is based off DS1+2 so may be completely wrong for 3. So far levelling seems to be slower in 3 as well. I feel like I'm over half way through the game and still only level 35. By this point in the game in 2 I was level 70-80.
The bonus of doing a blind play through first I guess
I'll probably end up looking up builds in my second play through. Though usually the idea of getting strength up first is a good one purely so you can experiment with weapons.
I haven't found any weapons yet that go above 35 strength. But in both previous games there were weapons and shield with a 50 strength requirement. So may be a safe bet that there are in this as well.
Edit:
Also the cloranthy ring is pretty much invaluable as a strength hero in the early game as it boots your stamina regen so even if you are chewing through it you can manage it better. A hint if you haven't found it
It's in the settlement after the section with the catarina knight and the flaming demon. There's a stone tower you can jump down to and it's in a box on the floor that's glowing white with the item inside it
