Before packing your suitcases is, ask yourself, "What items can I not afford to lose on this trip?"
Your answer may include items such as eyeglasses or contact lenses, medications, legal documents such as passports, or your laptop. Whatever the list, these are the items to pack in your carry-on, not in the checked luggage, which is at risk of theft, once it leaves your hands.
If there is still space in your carry-on, add a change of clothes and your most essential toiletries, such as toothpaste, to avoid inconvenience, in case your checked luggage is lost