Beside "lắm", we often use 2 more words for emphasizing: "rất" and "quá"
"rất" is an intensifier adverb which is used before adjectives, adverbs, stative verbs (yêu - love, thích - like, ghét - hate, muốn - want, cần - need, tin - believe, xứng đáng - deserve, hiểu - understand, etc,.) to emphasize them. "rất" corresponds to "very", "very much" or "really" in English.
Ex:
Bức tranh này rất đẹp. - This painting is very nice.
Cô ấy hát rất hay. - She sings very beautifully.
Tôi rất muốn đến Paris. - I really want to go to Paris.
Anh ấy rất xứng đáng nhận giải thưởng này. - He really deserves to receive this award.
Nhiều người rất thích phở. - Many people like "phở" very much.
"quá" is also an intensifier adverb which can be used before adjectives, adverbs, stative verbs (same like with "rất") to imply something is more than needed or wanted. You can think about it as "too" in English. The difference is "too" is mostly used to emphasize a negative meaning, whereas, "rất" can be used for both negative and positive cases. :)
"quá" can be used at the end of the sentence as an interjection for exclamation purpose. Here you need to use exclamation mark to end the sentences.
Chiếc váy này quá đắt. - This dress is too expensive.
Nam không thể quên được bạn gái cũ vì anh đã quá yêu cô ấy. - Nam cannot forget his ex-girlfriend as he loved her too much.
Phim hay quá! - What a good movie!
Cô ấy đẹp quá! - How beautiful she is!
Hope this won't confuse you. :)