Which structure is best to learn japanese?

[Laver2k]

Hello all!
I take a japanese evening class 2 hours every week and self study when i get the chance. This usually consists of maybe 30 mins on the bus every day and a few study sessions in the week. I find that my japanese class moves at a pace that is aimed more towards, well, showing off to friends or maybe basic holiday language.
I was wondering which kind of structure to follow to learn japanese professionally as I feel at the moment I am flicking around books picking up random vocab and grammar.
I can do the basics, talking about me, time, family, asking for help etc. I can conjugate adjectives into mashita, mashou and masen. I can read and write kana. Now I'm wondering where to go next because Im reading about the different adjectives and how they are altered differently.
So do I need 2 lists? 1 for i adjectives and 1 for na adjectives? Also, what form do I learn to start with, the dictionary form of each adjective?
I'd just like a little advice on the approach I should take into learning japanese on a higher level.

Thanks for taking the time to read this!

[maxiewawa]

Yes! You need two different lists, for two different kinds of adjectives. I think you should learn the basic form of ~i adjectives (~na adjectives don't conjugate so there's no form to learn).

So to start you off:

熱い・あつい　hot
寒い・さむい cold
大きい・おおきい big
小さい・小さい small

And a little big of conjugation:

熱くない・あつくない　not hot
寒くない・さむくない not cold
大きくない・おおきくない not big
小さくない・ちいさくない not small

[Laver2k]

Thanks .
na adjectives dont change? Are that just used with the na attached before the noun?

I can change the i ones into ~kunai ~katta ~kattakunai etc.
So how do I spot a na adjective? Does it just have ei at the end of it?

[maxiewawa]

They are hard to pick. I don't know how you'd pick them without knowing what they are... a lot of them are from Chinese, and are only Kanji. Can anyone else helP?

[tiroth2]

There is no way to know. But most adjectives ending in "-i" are true adjectives, and it's probably safe to say any "-sii" adjective is.

I think it is easiest to not consider these types of words to be adjectives at all. Just have one bin for adjectives, another for na-nominals (aka na-adjectives/nakeiyousi), another for forms that take "to", and just treat adj-no forms like normal nouns.