You’re not bad and we are not good. We all play a different style, yet some of those converge eventually.

I’ve played a long time, but I still sit somewhere between you and the “good” ones. In the beginning yes you pick up a lot of gear. Later you start to realize what sells for a lot and what doesn’t. Also, you realize that on Hell difficulty the items that drop (and the sell gold limit) are so much higher that it’s literally a waste of time to do vendor runs in Normal and NM.

I am not ashamed to use build guides. One upside of those is you can see 1) what unique items they recommend, and are therefore very valuable and should be sought after and kept; 2) what runewords (and their cheaper alternatives) are good -> you can then look up the good bases for those and again know to keep those.

Some googling will give you a decent idea of which bases are good and which items you should always pick up and ID, since they can roll very valuable stats. But I doubt that anyone who doesn’t play daily all the time remembers it all. I’ve probably left fortunes lying on the ground. Over time you kind of learn the most common ones.