Well almost everyone has a checklist of what to carry and what not to carry and also that it is wise to have a change of clothes etc with you lest the airline loses your baggage. However the question is how to be able to pack all the essentials for your next long vouage.
1. Get a weighing machine. You could even weigh yourself on your bathroom scale with and without the luggage and subtract the 2 readings to estimate the weight of your luggage. The sooner you do this the better idea you will have about what you can carry and what you cannot.
2. Get a ton of plastic bags: They are very useful in transferring excess goods around when airline carrier objects to the weight of your baggage.
3. Pack in layers: The idea is to create a whole section of items that you can toss in the garbage if the airline asks you to pay for the excess baggage. These could be very well those eatables which your mom packed for your long international stay or some useless trinkets that weigh a lot but don’t have much emotional or economical value.
4. Keep your coats and jackets on top: The fastest way to bring your baggage within limits is to temporarily put on multiple jackets/woolen wear. (You can take them down once you board the flight)
5. Remember to pack your valuables and electronics in a way that they don’t spill out during this shifting.
6. Pack compactly. The smaller the baggage size, the less likely are the airline officials to object to your carrying it.
However since the check-in baggage is always weighed but cabin baggage is not, your real creativity comes here.
7. Security measures require all passengers to screen their laptops separately from the rest of the cabin baggage. Exploit that by packing your laptop/any other personal electronic device in a separate bag. (you could put some additional items also in this bag.)
8. Girls should carry a big purse and guys a waist pouch. It’s amazing how much you can put inside them.
9. Get a small paper bag from an expensive store. If you pack right, that small bag can easily hold a few kgs while still giving the looks of an innocent expensive parting gift that you just now received.
The idea is that most airlines have a lot of tolerance for people carrying excess baggage and you should be able to exploit it fully.
All said and done, do travel light when you can afford to. The lesser weight you carry, the less fuel will be burnt flying it. Also please don’t try this above list if you are travelling in a low cost airline. Many of them see baggage handling as a revenue source and would charge you even if you are a few 100gm excess.