(thrifted Hudson jeans which have sadly bitten the dust by now)
Sadly, I find that the pant section in the thrift store has the lowest success rate for me. In general, pants are the hardest for me to shop for and this difficulty follows me into the thrift store as well. Pants deal with waists and hips and thighs and it's often a puzzle to fit all three at once. Finding pants takes focus and I would rather shop my feelings in the dress section. And while I don't think that pants will ever become my greatest thrift shopping strength, I do hope I can pass on a few tips. If you are a thrifted pants maven or ridiculously smart, please add your pants wisdom in the comments!
Try them on. Sometimes I am too lazy for the changeroom... Hanging up my purse, taking off my shoes, getting distracted and making duckfaces in the mirror; it's all a lot of work. On lazy days of thrifting, I stick to looking for skirts, dresses and tops, items that I have gotten pretty good at just eye balling to guess their fit. But if I am specifically looking for pants (like the jeans below, I was looking for a cheap pair to use for a bleach experiment), I know I need to try them on. Between waist, hips, thighs and inseams, there are a lot of measurements that need to fit to your body. So save the thrifting for pants on the days you have had your oatmeal for breakfast, or for days when you have artificially increased your energy levels with a tasty, ice-cold Rockstar*.
Look for brands that fit your body. This is especially relevant with jeans. I am going to take a slightly educated guess (I googled it) and estimate that jeans are probably the most worn item of clothing in North America, maybe even the world.
The popularity of jeans results in plenty of denim at the thrift store. While the blazer section might have every colour of the rainbow and synthetic and natural fibres thrown in together, the denim section has... just jeans. The closet turnover for jeans is high, so it is very likely that you will find denim from your favourite mall brand on the thrift store rack. I know I can be a bit hard on thrifting mall brands but brands like Gap, A&F and h&m all carry well-cut and well made jeans. If you know that Gap jeans have the power to make your booty look 10 years firmer, then keep your eyes open for some Gap jeans! Of course, since you are putting in effort by shopping for pants anyways, try on some other brands as well... I have also seen plenty of high end denim, which is good news for denim snobs (ie. myself in university). And as I've recommended before, look beyond whatever size label you assign your body. Your perfect pair of pants might be a size larger than you normally wear because sizing is all over the place at the thrift store.
Find what era suits you. In fashion, everything comes back into style at some point. In the past I hated flares and I hated pleated pants and then I took it all back and embraced both. I am fickle. So is fashion.
While you should still try on every pair of pants you deem to have potential at the thrift store, your search can be narrowed down by avoiding what silhouettes don't work for your body and embracing what silhouettes do work. The thrift store carries clothing from the past few decades, so there is a wide variety in fit and style. For myself, I avoid the lowriders of the early 2000's... mostly because I say no to crack and no to breeziness on the lower back. I also avoid the highwaisted vintage bellbottoms of the 70's... When I try them on, they make it up to my knees and then... that's it. Pleated pants from the 80's are much more successful. They fit snug at my waist and the pleats leave extra room for my hips and thighs. Figuring out what silhouettes from the past fashion eras work for your body type, will help you sort through the racks of pants and find success.
(thrifted and bleached out h&m jeans)
*Not a sponsored post. Though that would be awesome... Thrift posts brought to you by energy drinks? Clearly a good match.