What things about the English langauage should I know to be able to learn better?
I stopped taking English at 16, I never really like it or payed much attention. Now I'm trying to develop myself and I feel like I'm missing out on some basic understandings. I am trying to learn French now and am doing ok, however I feel like I'm missing somethings. Like I have no idea what imperative, infinitive and participle are. I understand verbs and adverbs etc. but much more it all gets a bit complex!
So what are the basics so I can understand my French lessons better?
The "basics" are more than can be explained here in a post! ;) There is a book called "English Grammar for Students of Spanish," or something like that. There is probably one for French, too.
Yes, there is :)
Go on Wikipedia and read up the articles about Grammar in general and English Grammar in specific. Look up phrases such as imperative, participle and infinitive, and whatever else you're not 100% sure about. It's a fantastic source of information.