。
She seemed excited.
Literal
She [topic-は] excited is [in-the-manner-of-ように] looked.
ように見える ('looks as if / appears that') uses the adverbial ように ('in the manner of') with the visibility verb 見える. Distinct from the alternative に見える, which marks a direct appearance state ('looks rich'), ように見える wraps a clause and reports a more clause-level impression ('looks like she's excited'). The clause inside is in plain form: 興奮している ('is excited'), a resulting-state ~ている.