General synonyms:
* Decorate
* Embellish
* Beautify
* Enhance
* Grace
* Ornament
* Trim
* Garnish
* Dress
* Deck
* Embroider
* Accessorize
* Augment
Words with a more formal or elegant tone:
* Embellish
* Grace
* Ornament
* Embroider
* Enrich
* Exalt
Words with a more informal or casual tone:
* Dress up
* Spruce up
* Pretty up
* Deck out
* Accessorize
Words that emphasize a specific type of adornment:
* Lace
* Embellish
* Embroider
* Incrust
* Bejewel
* Carve
* Paint
The best word to use will depend on the specific context and the desired tone.