比起……(来) and A比N还N: compared with…, more N than N
【高90】比较句 / comparison
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
比起 B (来)，A 更 / 还 / 要…… puts the standard of comparison first, as a topic: 比起唱歌来，他更喜欢跳舞 ("compared with singing, he prefers dancing"). B can be a noun, a pronoun or a verb, and the main clause almost always carries a degree marker (更, 还, 要, 多了) or a measure of the gap: 比起其他人，我的想法太简单了。 Without a marker, the sentence sounds unfinished.
A 比 N 还 N is a separate device: a noun is repeated to say that A is more N than N itself: 他简直比强盗还强盗 ("he is a real bandit, more bandit than a bandit"). The noun must stand for a recognisable type or quality (绅士, 强盗, 孩子, 老板); the tone is vivid, often ironic or pejorative.
Register: 比起……来 is current in speech and in writing; the more formal alternative is 与……相比 (HSK 6). 比 N 还 N is rather colloquial.
Examples
比起唱歌来，他更喜欢跳舞。
Bǐqǐ chànggē lái, tā gèng xǐhuan tiàowǔ.Compared with singing, he likes dancing better.
比起去年，今年的客人多了不少。
Bǐqǐ qùnián, jīnnián de kèrén duō le bùshǎo.Compared with last year, there are quite a few more guests this year.
比起其他人，我的想法太简单了。
Bǐqǐ qítā rén, wǒ de xiǎngfǎ tài jiǎndān le.Compared with the others, my idea is far too simple.
他这个人比孩子还孩子，一点也不懂事。
Tā zhège rén bǐ háizi hái háizi, yìdiǎn yě bù dǒngshì.He is more of a child than a child, and has no sense at all.
他简直比强盗还强盗。
Tā jiǎnzhí bǐ qiángdào hái qiángdào.He is positively more of a bandit than a bandit.
在上流社会里，他装得比绅士还绅士。
Zài shàngliú shèhuì lǐ, tā zhuāng de bǐ shēnshì hái shēnshì.In high society he plays the gentleman more gentlemanly than any gentleman.
Common mistakes
✗ 比起他来，我很高。 → ✓ 比起他来，我更高。 (比起 sets up a comparison: the main clause needs 更 / 还 / 要, or a measure such as 高多了).
✗ 他比绅士还很绅士。 → ✓ 他比绅士还绅士。 (no degree adverb inside 比 N 还 N).
✗ 这张桌子比桌子还桌子。 → the noun must stand for a recognisable type or quality (绅士, 强盗, 孩子), otherwise the sentence says nothing.