Well, Years back when I travelled for the first time, I remember asking my friends, my managers, HR and people around me as to what to take. I did a search in google too. Getting information is a very tough and tiring task. It is very stressful too. Let me help de-stress yourself.
Make sure to carry one pair of casual and formal wear in your cabin bag. Sometime arrival of baggage may get delayed.
If possible declare all these items when you leave airport so that when you come back there are no custom issues.
Make sure that one copy of passport and itinerary is kept in each of the bags you carry.
Keep all your documents in the cabin bag. Make sure all the bags are tagged in airport.
Take medicines that you think is very important for you. Would not list items here as it is personal to many and vary.
Printable format can be downloaded @