The number-one rule in packing for a trip is to pack lightly because we often forget how frequently we'll have to lift or carry our luggage during our travels. Consider how, you'll be dragging your luggage into the trunk of your car and out again, through the airport, off of the luggage carousel, through another airport, back into the trunk of your rental car and out again until finally you get to the hotel where hopefully they'll have a porter.
On top of having to lug your bags around, your airline will have strict rules on the size, weight and the number of bags you can travel with-for both carry-on and checked baggage. Make sure you check your airline's website for current information on restrictions and don't assume that what you took last time will be allowed this time-especially if you are travelling on a different airline. Luggage size and weight restrictions can vary by airline or travel destination.
Money-saving travel tip
Packing lightly for your travels can save you money. Many airlines are now charging fees for overweight bags, oversized bags, and for checking more than the allowed number of bags per passenger.
Other great reasons for packing lightly: shorter waits around the luggage carousel, less need for porters (and tips!) and easier Customs inspections (after all, if you had to force your bags closed, imagine how happy the Customs agents will be!)