It's somewhat gamified and broken up into levels and stages. Each stage has ten levels if I remember correctly. Every level introduces new radicals, and then once you've reviewed those a few times and gotten enough correct it introduces kanji that use the radicals. And then as you review those it introduces vocabulary that use the kanji. And you review those as well, and once you've gotten enough right enough times you move on to the next level.

Eventually if you get something right enough times, there's a three month gap before it shows it to you again, and then if you get it right that time it's basically completed and you won't see it anymore. Which is good because by halfway through you're already working with basically thousands of digital flashcards.

You might install an undo button because you get annoyed when a typo makes you get an answer wrong that you knew, or because you typed the kun'yomi when it wanted on'yomi, but the next you know you're convincing yourself that you really knew that one even though you just typed the wrong thing because it was a brainfart. So then you as start getting answers "correct" even when they could use more review. Next thing you know you're burning turtles (their phrase for completing an item) before you truly internalized the concept.

So yeah, be careful with plugins.

It can be tempting to skip the radicals if you're using plugins, but that will make the mnemonics make way less sense. So even though it's kinda dumb, you have to learn their names for the radicals. Even though if you call it that in a real japanese class or to a Japanese person, they'll look at you like you don't know what you're talking about. On the bright side though, they'll be super impressed when they see you have no trouble reading kanji on a menu or whatever.

Oh and practice organizing your flashcards into a table that goes 「あ、い、う、え、お」 down the right side, and 「あ、か、さ、た、な、は、ま、や、ら、わ」 across the top (from right to left). That might sound weird, but try it! It will help you organize the characters spatially and you'll gain a more intuitive understanding of the relationships and patterns between them. It'll feel less like a giant messy alphabet of squiggles, and more like a coherent and orderly system of phonemes.

It'll also show you which ones you still struggle with, because you'll be able to see the holes in your table (if you're doing it without looking at a reference, which I recommend. Do as many as you can without it, and only then check your reference to fill in the rest). Then you know which ones to focus on. And each time you build the table, those holes will get smaller until you can put each one in its place without checking any references.

At that point, it'll feel so easy that you won't even know why you have flashcards anymore. But keep using them until you can write each character too. Again, try filling in your table, only this time writing them by hand each time.

Once you can do all that with the hiragana, you can make your katakana flashcards. Only, skip the romaji this time. Make your flashcards flip between the hiragana and the katakana!

If you want to be able to write by hand, you have to practice the stroke order. It's the only way to ingrain it in your memory. The Kodansha books will give you all you need for that. If you prefer mobile apps, Jsho and Imiwa both have that information. I think Imiwa is better than Jsho, but unfortunately it's not on android.

Shadowing is good for listening and speaking practice. 日本語話しよう is a good textbook/cd for that, or you could probably find videos on the internet. After that, just watching J-Dramas and listening to Japanese music. Avoid using anime for practice sessions though because that's not how people really talk.