Tips for making one language sound melodic, and one sound harsh?

Warning: Long post

In my conworld, the main character's native language is Sovachian, as he was born in Sovachia's capital. I'm a bit unhappy with some of the vocab, and want it to sound more melodic. Not Italian/Japanese level of melody, but close to. Can anyone give me some tips on how to make my lang sound more melodic? Not just in its phonology, either, but with phonotactics and stuff like that :)

(To give an idea, Sovachian's name in Sovachian is pronounced /sɔ̟ːvˠăt͡ɕʰiˈɛ̃n/, and I'm not changing it)

My main character, in the beginning of the story, lives in Arengor, the polar opposite of Sovachia. Instead of a hot capital, varied landscapes, and being extremely rich, this place is cold, mountainous, and extremely poor. Even the wealthy are poorer than the Sovachian middle class. So to add to the contrast, the language, Aregonian, is gonna be harsh. Any tips for making this language as harsh as possible, while still sounding human? All I've decided about it is that it's gonna be agglutinative instead of fusional

PS. If any of this sounds weird, it's half past midnight, and I'm extremely tired :p