1. Chronicle what you have in your closet that needs a match or know what you want in general. The best way to do this for the first part, is to take pictures using a camera OR your phone. I pull out whatever I need a match for, and then snap a picture and then stick the camera or phone in my purse. If you're just looking for something specific that isn't a match for anything, make a list! You don't want to come home to realize that you never even looked for those vintage earrings!
2. Dress well. Wear a top that's not too loose. Some thrift stores don't even have fitting rooms so a tank top or fitted t-shirt is best. On bottom I find it best to wear a skirt preferably with an elastic waist and plenty of flare. I like these because you can easily slip it off or even slip things on underneath it with minimal time wasted. Clearly I was thinking of chicks here, but generally guys don't go through as much when shopping because the sizes are much less complicated. Not only that, but they don't wear clothes that take ten years to remove.
3. Take your allergy meds. I put this here for laughs, but on the other hand, I have dust allergies and I'll itch and sneeze the entire day if I forget to take my allergy pill.
4. Be focused. Thrift stores are not the same places they were when I was a child. They are-because they still have some of those same clothes lol-but they're not. Now, it's not unusual to see clothes at least sloppily color coordinated, and arranged by type. Don't go through all the shirts if you specifically want a pink one, and if you're looking for a vest, come away from the pants!
5. Get dirty. Sometimes treasures are hidden. If you're looking for a perfect vintage suitcase, don't be afraid to pull out a few and see if there is one underneath. In second-hand shops, it's the norm for things to be piled up on top of each other. The pros also use this handy knowledge to hide things to come back for if they can't find it cheaper elsewhere.
6. Be picky. Remember where you are. Check for tears, stains that may not come out, and missing components to items. If you're okay with sewing on that button or that tear at the seam, go for it! If not. Leave it.
7. Keep your eyes open. If you want to move on to pro status, know what tags are a percentage off for the day and specifically pick up items under that color. Victory will be all the sweeter for your work.
8. Take a second glance. There are times when you see a shirt and it looks "ehhh" on first glance...Occasionally on second glance it looks better. Once in awhile try on things that you're unsure of and come out of your comfort zone. I've done it before and got compliments all over the place :-)
I hope this was helpful to you! Are there any tips I left out that you'd like to add? Let me know in the comments!