conversation in the plain style

MNN20-3

particle omission

か as question marker becomes rising intonation.
は、が、を、へ(に)if meaning clear from context.

に、で、から、まで、と not omitted as needed for meaning.

contraction

〜ている becomes 〜てる
〜ちない becomes 〜てない

だ omission

In questions and answers with noun and なadjectives. だ is often omitted.
だ in an answer can sound harsh (also masculine). can be softened to だよ (or just よ for female speech)

けど

same function as が meaning but.