The particle に. I don't know why but I'm getting very confused about where to use it. I took a break from my Japanese (bad idea!) so I could focus on my GCSE exams and unfortunately, the に particle fell out of my head. Where would I use it? Can I use it in sentences such as: ここに電話をかけてください?
Also, when referencing days, I don't use it then, right..? Do I just use は? I know it's 今日は (e.g 今日は勉強します) but is it the same for あした or きのう? What about days of the week?
When referring to people as a collective, like 俺たち, does it matter what the group consists of? For example, I noticed a man say "俺たち" whilst he was with a woman. I also heard someone say "僕たち"-- there was a woman there. Does it depend on the speaker, or should it generally consider the group?
Also, if anyone's interested, I've started up a wiki which will (hopefully) turn out to be a good resource for sentences for SRS (space repetition software) programs such as anki (similar to electronic flashcards), as well as a few other things. If you're interested, please help out/comment on what could be better: 日本語 Mnemosyne