New vintage shopper

I've finally come to a conclusion. I must learn how to buy vintage. Surely there is a special technique that only certain people can know though, right?

Nope. 

I did a quick google search on how to identify authentic vintage and out I went to the thrift store. My goal? To find some cute vintage items to sell in my Etsy shop. You see, I have tons of ideas for sewing, but I also get caught up in the alterations, the custom orders, and just my own mind (wow that sounds bad). My main thought process is to make mostly vintage style clothes-very feminine-and even some maternity, but these things take time. So, here it is, my birthday and mom blesses me with her presence and goes with me to the thrift store down the street.
I specifically skipped Goodwill, just because I didn't want a place that charges the same for all like products (i.e. all skirts for 4.96, all books 1.00) and instead shop where all things were individually priced. It seemed more like a treasure hunt that way.
I took all the tips I learned from the internet, and began my search in the dresses. I was amazed that there were so many to choose from. I did use my search engine from my phone also to look up specific brands etc. I ended up buying only one dress though, a size 14 that my mom said they called a "shift dress" when she used to wear them. Honestly I was a bit nervous as a newbie buyer (although long-time admirer) of vintage and didn't want a bunch of stuff that I personally wouldn't wear that I'm trying to sell. As I paid a hefty $2 for my dress (it was like the cheapest dress there) the cashier remarked on how cute it was.

I got it home and tried it on to take pictures in it and realized that I must keep it. It is perfection-remember this is all in the eye of the beholder. I'm on a weight loss journey, and it's a teeny bit snug, but it looks great on my dress form which is a little less well-endowed in some areas than me. 

What are your thoughts? Do you have suggestions as a seasoned vintage shopper?