WaniKani is a web-based app that uses a spaced repetition system (SRS) to help you memorize Japanese kanji and vocabulary. (Tofugu makes this, which means this is a shameless plug.)
When using WaniKani, first you'll get familiar with the radicals that make up the kanji you're about to learn. Then, you'll study both the meanings and readings of kanji through mnemonics, or silly stories that stick in your mind. Finally, you'll learn important vocabulary that uses those kanji and review them to oblivion in your Reviews queue.
In total, WaniKani has sixty levels to complete, after which you'll have learned 2,000 kanji and 6,000 vocabulary words. As you level up, you'll eventually "burn" items (meaning they're fully burned into your noggin) and see your slow but steady progress. At its fastest pace, WaniKani can be finished in just over a year, but most people take longer than that.
Additionally, WaniKani provides a community forum to bond with other learners of Japanese, so you won't feel alone in your studies. The site also supports third-party apps/plug-ins through our API, meaning all the innovative tools WaniKani users have come up with throughout the years are at your disposal.
The first three levels are free, so you can see if it works for you before you commit to a monthly/annual subscription or spring for a Lifetime membership. The crabigator awaits!