Just in case you're not reading VNs but still practicing English, try watching sitcoms.. Sitcoms contain a lot of idioms that are really necessary when learning English..
You need to stay away from action driven shows (CSI, The Walking Dead, or comedies heavy with slapstick). It's because if you turn down the volume and just watch the movements of the actors, you still get to have an idea where the story is going. Like who was the killer or how this artifact saved the day. It's not the case for sitcoms though, you turn down the volume and you just see them talking so your brain has to spend some time understanding what's going on and of course, you end up not understanding the humor. There are a lot of pop culture references in sitcoms that you may not understand so the joke may not appear funny but don't let that discourage you. It will eventually work out
By the way, the most difficult thing I had with English (until now) was the use of prepositions.. Try to work on that as well :D/>
--- Grew up watching Spin City, Friends, Dharma and Greg, 8 Simple Rules etc. etc.