this is your first time through the game, yes? if so, then yeah, good thing you didn't get the master key. might end up getting lost unlocking doors that you should save for later!
can't go wrong with vit and end, for sure. strength for the big, slow weapons. dex for the fast, light weapons. generally speaking of course, since there are exceptions to the typical str/dex weapon.
don't bother with resistance.
intelligence for magic spells, faith for miracles
the game doesn't tell you how to get more uses out of your estus flask, so i won't feel bad about just telling you straight up how to do it.
use a humanity item when you're next to a bonfire. might as well use two right away. you should see 02 on the top left corner next to your health and stamina.
sit next to a bonfire. choose "reverse hollowing". your zombie character should look human afterward. then choose "kindle". that should bring up the number of estus flask uses to 10 whenever you sit on that particular bonfire you just kindled.