Sit down and do some thinking and some homework first. If you like to stay up late, then maybe you want to sign up for the second dinner seating. If not, maybe you should take along some accupressure wrist bands, motion sickness patches, or medication. Buy a rolling suitcase. I favor the rectangular kind that flight attendants and pilots use.
Discount stores carry good-quality ones for reasonable prices.
Remember that no one is going to care if you wear the same shirt twice. When things are dirty, you can hand wash items at your lodgings, or visit a local laundomat. And if you pack light going to your destination, you'll have room to pack your souveniers on the way back. If you are flying, check your bags. The truth is that airlines are much, much better than they used to be with regard to not losing your luggage, and in general they are getting checked bags to passengers more quickly after a flight in the terminal.