From 2010 studies again...
I was surprised to discover while on my nearly-month-long trip that I knew a bit more French than I thought I did. I had some French magazines and a book to read, but no dictionary, so I was forced to try to read without looking up words I didn't at first recognize. This made me pay more attention, and made me dredge my memory for vocabulary and verb endings -- and lo and behold, I could make more sense than I expected. I guess what I learned was how to skim in French, searching for as much meaning as possible. I didn't know all the words, but enough to make sense of some simple writings.
I noticed when I got home that I am actually almost halfway through my great reading-French textbook, so it's not surprising that I can read something by now without a dictionary handy. However, it's also not surprising that when I downloaded a history magazine in French a couple days ago that I found that its style was much more complex than I had been reading on my trip, and with lots of new vocabulary (unfortunately many to do with assassinations, which is not fun). I still have loads to learn! (Though would be perfectly happy to skip the gross bits, thank you.)
But I think the moral of my story today is, try to skim your foreign language at some point. You might know more than you thought you did.