it might take you a while to find exactly what you're looking for. it took me a year to finally find overalls at a thrift store. you need patience when you're looking for that hidden gem, it's out there.
if you want to be trendy then thrifting might not be the best way to do that. you can't find the latest bubble necklace at your local thrift store. so you might have to be creative and change your style a bit.
keep a list.
this is essential for me. i keep a list on my phone of all the things i want to buy, shoes, pants, blouses, etc. it helps me too look for specific things when i'm shopping, then i'm less likely to make an impulse buy.
have a budget.
if you just walk into a store with no budget you are more likely to over spend. when you set a budget for yourself you buy the things you really need/like and are forced to put the others back.
you have to be able to walk away from something. remember it is only clothes. when something is not the right price or over budget, simply walk away.
get rid of things.
don't be a pack rat! my rule of thumb is if i'm buying new clothes then i need to give old ones away. it is easy to become a pack rat when thrifting but not if you set up rules for yourself.
like it or leave it.
a lot of times i will buy something because i want to make my trip worth it. don't do that! if you don't absolutely like it, then don't buy it. because chances are that it will be sitting in your house or closet collecting dust. i can't tell you how much money i could have saved with some of the things i bought.
these are some of the thrifting basics that you need to know before you go out there. most important is to always remember that it's not the clothes that make the person but the character.