I'm inclined to agree with Steve Kaufman that the new uses of "hack" and "hacking" can't quite overcome the negative connotations. His video is short and sweet, and I won't share what is in this video...
Instead, I will describe my language learning "hack".
I've been at language learning for decades so there is no question in my mind that language learning takes a lot of repetition. Sure, some words I learn quickly or even immediately. But for most words and concepts I need a lot of exposure too before I learn them.
My hack is that I want to focus that required repetition on what I don't know, and spend far less of my time repeating words and phrases that I do know. To help reduce the unnecessary repetition, I keep track of what I'm studying in a language learning notebook and on this blog. I keep the notebook so I can practice hand writing and cursive. I started keeping lessons on this blog because it's far more likely that I'll communicate with people via computers than paper, so I want to be able to type.
Basically my typical daily routine is to study foreign language via any of various means, and while doing that I keep notes about the source and the new words or grammar concepts that I'm learning. Sometimes I create a list of words or phrases. Other times I write out sample sentences to practice a grammar point I'm trying to understand. Some days I'm repeating past lessons. Some days I'm looking for new sources for concepts and words I'd already studied. Some days I'm charting new territory. A few days I have enough time to do all three of these activities.
I don't worry about the format of my notes, or language learning notebook. The only constant is that I want to keep track of what I'm learning by date so that I can go back over it and see what I need to review. Most days I check back a few weeks later and self-assess to see what words and phrases that I remember. Sometimes I'll even go back a few months later if I need to remind myself that I am learning a lot.
Recently a Russian man that tries to solicit tutoring in a language forum I use insulted my progress because I forgot how to spell a very common verb. Though I was tempted to remind him that you can catch more flies with honey, I reminded myself instead to keep it positive. Keeping track of what I've studied on this blog and in notebooks helps me keep positive and stay motivated. I can go back many months and read most of what I've written in the past. Let's say I can read 95 out of 100 words. That's a fantastic reminder of how much I'm learning, and yet also a fantastic way to identify those 5 words that I need to review.
If you've looked around my blog at all, you can surely notice that keeping track of some of my language learning on this blog doesn't fit with "blogging" by the standard definition. I never really got into blogging. There are a few bloggers out there with language blogs, but I'm not interested in creating a theme blog and trying to fit into a community because chatting with people in comments on blogs would take time away from learning languages. I figured that out 10+ years ago when I first started this blog and tried for awhile to make it all about writing romance novels. I spent so much time social networking back then that I didn't have time to write. So I started to use this blog to keep track of things that interests me and stopped worrying about attracting followers. I figure that the people that do show up via search engines can look up what interests them by searching or using the tags.
When I need other sources to remember some words and phrases, instead of mainlining custom Anki flashcards, I tend to save pins on Pinterest for images, look on Twitter for sample sentences, and listen to the pronunciation sound file from a site like Forvo.com.
By the way, here is the label for foreign languages at lifehacker. It isn't a huge topic over there. Which to me is a little odd because even though I too think making flakier biscuits is cool, I think language learning is the ultimate life hack.