。
She's particular about what she wears.
Literal
She [topic-は] her own wear-things [as for-には] is-fussy.
やかましい (literally 'noisy, loud') in figurative use means 'fussy, particular, picky' — applied to people who hold strict standards in some domain. The composite particle には scopes that fussiness to a specific area: clothing, here. 自分の着るもの ('the things she wears') uses the dictionary-form verb 着る attributively to modify もの — a relative clause sitting before its head noun. The plain present gives a habitual reading: this is what she's like.