I've been studying Japanese for a few months now, but I'm still struggling to understand the basic concepts of sentence structure. When I began studying Italian, I never had this problem, I guess because it was very similar to English in certain ways (how sentences are put together, how verbs and adjectives work in relation to one another). However, in Japanese I'm still stuck on "exceptions", by which I mean I can understand how to use デス、でした、じゃりません、じゃりませんでした, but don't understand the general rules for conjugating verbs, I can understand な-adjectives, but not adjectives in general. I'm quite a scientific person by nature, and I like understanding the rules of a system (in this case grammar) before anything else.

Can anyone reccomend good resources for rapid learning of these concepts, or concise explainations of how the language as a whole works?

I'd love to hear about other people experiences learning languages that are very different from their own (not just English to Japanese :) ) and hear about the challenges they had.