Dragging heavy suitcases around airports and onto public transport quickly becomes tiresome. The less you have to carry, the happier you will be travelling. Check what the weather will be like where you’re going, then pack only what you’ll need.
If you roll your clothes when packing, you’ll fit more in your case and they’ll come out with fewer creases. Rather than carry heavy books, charge your tablet or devices before you go and load them with things to read, play or watch. And keep a change of clothes and basic toiletries in your carry-on bag in case your luggage gets lost in transit.