Regarding gear (rares, not uniques) learn the stat tiers that each item can have. That'll learn you what separates an OK item from a Good item from a zomfgGREAT item.
I know must off them by heart now but PoEAffix is my go-to if I can't remember something.
I don't know if I am missing something, but how can you tell what weapons are good using the PoEAffix site? I clicked on one handed axes and all I see is a list of base Mods, master mods etc. I was expecting a list of items with names and how to acquire them.
I'll have to take a bit of time to read the Wiki to learn how to calculate dmg in this game. Seems a bit complicated at first glance, but I am sure once I get the base equation it will be easy to figure out. I learned the hard way not to rely on the DPS # on our Char sheet. Same as D3 I guess.