I use flashcards to learn Japanese kanji and their English meaning. I put Anki on my tablet and go through the assigned number of cards every morning. This is mainly a tool to get me to the point of initially recognizing the kanji. I haven't found an alternative to repeated exposure and use to get them firmly in my memory.

Usually I just chat a lot to people, listen to songs and sometimes read books . I do it a lot everyday and step by step I learn new things. Even if you know a lot you need to practise it as much as possible

50 words a day is possible, but a very bad idea, because it's temporary. Most people who memorise just 20 a day don't use the language enough to make them stick, regardless of what they say, otherwise we'd be seeing a lot of wise ass kids on the internet becoming very skilled very fast. 

Regardless, sometimes mnemonics can be useful. I use them, only as a last resort, to memorise vocabulary words, especially for non-latin scripts, and chinese characters. If you can learn it without a mnemonic, do it.

Flash cards help a lot and I definitely need to be more strict about learning words on a DAILY basis, it works so well for others. 

I also use sticky notes and place them around my flat for the Russian equilivant but that can become slightly annoying. :)

If I need to remember word, I'm serching simple sentence with this word. And then i remember meaning of the word for a long time.