Mind mapping can help you. You just set the vocab in categories you need to remember each day.

You practice using each word by making sentence or even in conversation.

You need to find the suitable way could help you memorize since each one has different style in memorize.

As asking for app and www, it has many so you just use google to search for.

I used ti use picture dictionary by Oxford it helps me a lot.

Hope my idea can help you.

I've used the underlying website and have got a proper feedback.

https://www.memrise.com/home/

You can try connecting the word with a picture or link it up with something you find similar in sound and meaning to help you remember it. Here is a good dictionary that does that -  https://mnemonicdictionary.com/ ;