Bags lost on an international flight are governed by international law, which sets a cap of about $1,500 per passenger. For flights within the U.S., a new cap of $3,000 per passenger was set in March.
Aside from the obvious such as reporting lost baggage as soon as possible the article has good advice on getting (partial) reimbursements on you essential toiletries and reminds you that most airlines don’t cover electronics, so carry your laptop with you. If your luggage is found after you’ve received a reimbursement, most airlines won’t make you pay it back.