OP, is your problem getting the motivation to study or that you actually can't remember the things after you've learnt them?
First you have to accept that you will never remember everything, so don't beat yourself up about that. I suggest that you make some kind of timetable with small, manageable goals e.g. doing the reading exercises to chapter 1 today, doing the listening exercises tomorrow, revising 10 kanji the day after etc.
I can tell you what I did but you have to assess for yourself after a few weeks, is this method working for me? If not, do I need to listen more? or write more?
Do you copy everything from the book/website and write it on a notebook?
I don't copy EVERYTHING because that would take forever. But for me writing things out really helps.
Usually I will read through the dialogues while listening to the CD - if you don't have a textbook with a CD, I recommend you get one. I pause the recording and go back over difficult passages. If there are reading passages I will read through them and look up words/grammar if necessary.
Then I will go through the grammar points, writing out example sentences and a short explanation for myself in my notebook.
I copy down new vocabulary from this chapter in my notebook only if I think it is approximately my level or I think it is useful for me e.g. when I was pretty much a beginner I would not bother writing down the words for "division of labour" or "political coup", but I might write down "travel insurance" because it's useful and I want to remember it. (picking random words here...)
I did exercises and copied out kanji in a separate "rough" notebook, so that my "neat" notebook was a good reference when I wanted to review what I'd learnt, especially grammar points.
In addition to the textbook, I reviewed kanji just using a list from the internet by copying them and the readings out, I watched Japanese TV with subtitles and I talked to Japanese people via text chat.
I certainly hope the state of college education isn't so poor that it would require a BA in Japanese to be able to pass a test intended for those who haven't even finished elementary school yet.
OT but I was researching this recently out of curiosity and it seems a 3-year BA in Japanese leaves the majority of students with about N2 level. Pretty pathetic IMHO... for a UK or US amount of tuition you'd be better off paying to go and study in Japan for a year or two (yes I know many people can't afford to because they need student loans, but I still think it's a rip-off).