It depends on your objective. If you want to learn to read, then kanji is obvious.
If you only want to talk for now, you should probably learn some grammar.
I would start learning grammar after mastering the level 1 vocabulary.
Sentences and phrases are nice practicing material for new (and old) students, since they have Words, grammar, kanji, kana and everything. Learn a few phrases, and analyze them. "What gives the sentence the meaning it has?" and so forth. This, alongside with vocab, kanji and grammar separately works wonders (for me, at least).