Too many buzzwords
While you're searching for a hostel online, look at the hostel's description and try to read between the lines. If a hostel says it's cozy, don't be shocked when you arrive to find yourself in a tiny room with 7 other roommates.
A quiet place usually means the guests will be older and may have more of a hotel feel to it. Hostels described as quaint or charming may very well be old, drab and dreary.