Seasoned travelers, both international and domestic, will all tell you the same piece of advice. Never check in luggage.
Packing minimally is an art learned from experience. Getting to a destination and not needing half of the things you packed is a good sign you need to plan your packing more carefully. Check out the great info-graphic from Save Spend Splurge.com to help you whittle your luggage down to the essentials.
My favorite tip—pack a empty fabric bag to bring back all the goodies you bought.