Coremu12 san,
Here are a few practical tips to remembering vocabulary:
1. Review at night in bed before you go to sleep. Ten or 15 minutes before your eyes close. This is just one study...there are quite a few more you can find online:
Study Before Bed for Significantly Better Retention
2. Engage as many senses as possible when you learn new words
As Nekojita san said, write it (physically), see it, say it. When I say "see it," I mean see it as you write it AND imagine it as well. See the representation of the word vividly in your mind. Sure, there are some words that are hard to visualize, but you should be able to come up with something for most words. This is also a good chance for you to practice your writing in hiragana, katakana, or kanji.
3. Play with the words
As you're writing, try and make a sentence or two with the word.
Ex. denwa (phone)
1. Write the word. Write, write, write. Say it, see it.
2. Write a short sentence and say it out loud. Denwa wo kakeru (to call someone). Denwa de tsutaeru (to tell someone [something] by phone)
4. While you're at it, learn the particle that comes frequently with that word
Is it a "ni" or a "de?" "Wo?" Ex. Au (to meet). Au takes the particle "de" before it when you're talking about a location/place (eki de aimashita = I met [her] at the station; resutoran de aimashou = let's meet at the restaurant). It takes a "ni" when you're talking about a "who" (Ex. Obama daitouryou ni aimashita = I met President Obama). You can even string a longer sentence together here. Eki DE Obama daitouryou NI aimashita = I met President Obama at the train station. (If you REALLY want this to stick in your memory, make it a dramatic scene out of a movie...and make the person you meet your...ahem...significant other. Or your dream significant other.)
5. Review, review, review
Hope this helps. Don't get frustrated. Like Steve Martin said, "(Foreigners) have a different word for everything."
That's truly the case for a language like Japanese. Stay consistent, work hard, and one day it'll "click" for you.