The more… the more…: 越……越 / 越来越
固定格式 / fixed patterns
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
A 越 V1，(B) 越 V2 ｜ Subject + 越来越 + Adj
越A越B: "the more A, the more B". The change in B depends on A: 你越说，我越不明白 (the more you talk, the less I understand).
越来越 + adjective / psychological verb: "more and more". It describes change over time: 天气越来越冷 (it's getting colder and colder).
Since 越 is already a degree adverb, never add 很, 非常, 太… after it: ✗ 越来越很好.
Examples
他的身体越来越好了。
Tā de shēntǐ yuè lái yuè hǎo le.His health is getting better and better.
雨越下越大。
Yǔ yuè xià yuè dà.The rain is getting heavier and heavier.
你越紧张，就越睡不着。
Nǐ yuè jǐnzhāng, jiù yuè shuì bu zháo.The more stressed you are, the harder it is to fall asleep.
我越来越喜欢早上跑步了。
Wǒ yuè lái yuè xǐhuan zǎoshang pǎobù le.I'm enjoying morning runs more and more.
Common mistakes
✗ 天气越来越很冷。 → no degree adverb. ✓ 天气越来越冷。
✗ 越来越我喜欢。 → subject first. ✓ 我越来越喜欢。