Always carry on bag with you and keep the list of items with you.:

A passport for all travel outside the country and for identification purposes.
Travel wallet for carrying passport, boarding pass and all other travel documents.
Insurance cards for both your medical and automobile insurance.
Credit Cards.
Traveller checks.
Discount Coupons.
Airline, Cruise and Train Tickets.
Intenerary with confirmation numbers, addresses and phone number where you will be staying.
Travel brouchers and maps.
Lots of crisp one dollar bills for all those tipping opportunities.
A small amount of local currency for immediate use to hold you over until you can make it to a currency exchange if you are planning foreign travel.

Always Lock your Luggage:

This prevents accidental opening . There are new luggage locks which are
accepted and recognized by the TSA (Transport Security Administration)Which can be opened without damaging locks.
They have set of codes and tools to open TRAVEL SENTRY locks for efficient screening and inspection

Or you can use ZIP TIES from the luggage store.
Using a luggage strap is highly recommended for larger pieces (26" and larger). This will also prevent accidental opening, and help identify your luggage at baggage claim.

Remove any detachable

Remove shoulder straps, hooks, and ad-a bag straps, etc. any item that might get lost or broken.

Always Pack Light

Try not to take lot of clothes and lot of pair of shoes with you.
Try to take not more than two bags for each person traveling as some airline allow you two carry on so no hassle of checking the bags with the airlines (please check your airline for carry on size restrictions) mix and match clothes and before you travel check the local weather of places you visiting this will avoid you carrying stuff you don’t need.
Use Packing cubes and Folders to pack your stuff it saves lot of time and space and you know exactly where you kept your stuff.

Make a list of stuff

Always make an inventory of stuff carrying with you as coming back home and when you Re-pack you should not leave anything behind.

Do Not Carry

NEVER pack explosives, combustibles (gasoline), food of any kind, liquids, or pets. These could cause damage to your stuff and also it is against Air lines rules and regulation.