[maxcan]

This may come off as a little inappropriate but one thing I think about when learning another language is the usual mistakes or quirks that native speakers of that language display when speaking English. It turns out that quite often those are reflective of the correct form in their language.

It's helped me sound more natural in Japanese and Hebrew.

[wvh]

I speak a bunch of languages, and this is especially helpful when learning languages that have a specific own idiomatic sentence structure. You get a pretty good insight into how people form sentences in their native language based on how they garble English. You can often derive where people are from based on those typical mistakes, even in a few sentences on an online forum.