As a general rule crochet or knit items need to be treated with a smidge more delicacy when washing.
Typically it's best to pop your garment in a washing bag if planning on machine washing but make sure to use a gentle or wool cycle to avoid shrinkage!
If you're going down the handwashing route, make sure to use luke-warm/cool water and wash carefully to avoid any pulls or snags.
Ensure that after washing your piece is laid out flat and left until dry.