I am struggling to remember a lot of the words, any ways of remembering them?
Keep you tree gold and don't despair. At some point the pieces will fall together, I assure you...
Try TinyCards! And if you really want to go all the way, then do Duolingo + TinyCards + the official Memrise German courses.
I also recommend keeping a journal of words you learn, remember to note their gender too.
1) Online flash cards . I have tried Memrise (memrise.com), which is more concerned with vocabulary than grammar. There is also Quizlet (quizlet.com), where you can make your own flash cards (or choose the ones that are already made) and view them or even play simplistic games with those words. I do like the idea and options of Quizlet, but it wasn't really for me. 2) Excel. I guess I prefer the simplest way possible. I make one column in English, the other in french (That's the one I'm learning currently). Then I copy one of them separately, write the translations and correct them. I then exclude the words that I know very well and work on those, which I can't remember or have minor mistakes. After I feel strong in those as well, I do one more round with all the words.
Tips: 1) Don't learn a huge vocabulary all at once, divide them. You can't learn the whole dictionary straightaway. 2) Most times I try to find some kind of connection for the word in another language or try to associate it with something. ("Froid" is "cold" in French and somehow associates to me with Sigmund Freud or "blanc" is "white" and sounds like a blank page aka white.) Some might be more difficult and then I just try to dig them in my head. Also if you have just a few words that are difficult to remember, then try writing them in notepad or on paper over and over again. 3) If words themselves are difficult to remember, try remembering them in a funny sentence or order. 4) If you have problems remembering genders, then I suggest writing the vocabulary down and always using the specific sides (like left for masculine, middle for feminine and right for neuter) and stick to that layout. You might start remembering on which side you have seen the word, therefore remembering the gender. 5) It's all about repeating them. Just because you learn the words today, doesn't mean you will remember them after a week, if you don't use them. I actually keep those Excel pages saved and if I think I'm starting to forget certain vocabulary, I can just open up that document and practice again.
Generally I write all my vocabulary down in a notebook (as well as difficult sentences + grammar rules), but I practice remembering them in Excel or here in Duoling.
I guess it all depends on what kind of learner you are - some people, like me, prefer to do it as simple as possible, some need a stimuli like pictures or games. Test out what suits you and stick with that routine.
Tinycards (Web) for Portuguese does not have pictures for many words!
Using multiple choice (as in my very short Tinycards test) questions also will NOT help you IMHO for improving your RECALL (EN-DE) words rate.
I am not sure if that is only happens for the learning mode (like with Memrise 6 flower planting steps), or also in testing mode (you can disable multiple-choice in Memrise for reviews (and errors) and replace with typing).
Depends on the topic / group of those words:
You might better remember words in a full context, story telling, not too short sentences and not weird (unrealistic) sentences.
Try www.lingvist.com. That is the suggestion of many other users on DuoLingo (I am not using it already).
This is how I do Memrise and with what user scripts: https://www.duolingo.com/comment/19892868
Sorry, I have not translated that posting written by me in native German to English. Hopefully you have success with Google translate and other services.
I have just started using Tinycards and I found it really helpful. Why don't you try it?