When I'm teaching Japanese I often hear my students worried voices saying things like "I just can't remember all these new words and phrases...don't even get me started on the kanji!!" or "Even if I do try to memorise things, I just forget them straight away..."

Without a doubt, whatever the student's level, in order to improve their Japanese ability they need to "memorise" language.
Be it repeatedly writing out, listening to or reading new words and phrases, I think everyone must have their own varied devices for learning them.

Here I'd like to introduce a few sites and videos designed to help learners with their memorisation skills, particularly people who feel they have some trouble in that department.

I can't remember hiragana and katakana!

Kana cards to print and practice （Introduction article）

This is a site where you can make your own set of kana cards, simply by printing and cutting them out.
You can carry your cards when you're on the move, so you can keep working your way through them, wherever you are!

I can't remember words, expressions and kanji!

Anki （Introduction article）

This is a versatile tool that can be used for all kinds of purposes - learning words, kanji in context and expressions.
Anki is a spaced-repetition system, where you make your own computer-based flashcards. You can freely enter the word, phrase or particular kanji you want to know, then decide how well you can remember it to determine when the card will next be shown. As you continue reviewing over a period of time, using the program consistently means that the cards will be set to appear just at the time you might b close to forgetting how to use the phrase/kanji on them.

Kanji Koohii （Introductin article）

This is an online tool created to help those who are learning the kanji using James Heisig's "Remembering the Kanji" series of books.
The site has flashcards for all the kanji from volumes 1-3 of the series, and you practise writing the kanji from the keyword provided. You can add your own stories you use to remember the kanji components as per the Heisig method. The number of kanji you have memorised and those you have not yet mastered are clearly displayed in a very visual way, so it's easy to manage your own studying.