Carry-on only what you’ll need and your valuables. Basic toiletries, maybe some clean underwear for a long flight, books/magazines, cassette tapes, cassette player with headphone, camera, extra film, inflatable pillow, luggage keys, make up, medications, moist towelettes, reading glasses, bottled water, sun glasses, sweater, travel organizer, and warm socks or slippers. Also, carry your expensive items. Don’t check your cameras, and if you must take your best jewelry carry it with you.
Keep in mind that each carrier has it’s own rules about what qualifies as a carry-on bag. American, Delta, JetBlue and United changed their rules in the summer of 2014. Their size limit is now 22x14x9 inches with a maximum weight of 40 pounds. Southwest still gives you the largest carry-on bags. They changed theirs to 24x16x10 inches. They also request that you place them in the overhead bin with the wheels facing out. Always remember to check with your airlines for the most current info. Always check with the operators of your connecting flights because their rules may be different, especially smaller regional carriers.
Many foreign carriers also have the reduced carry-on bag size because their overhead space is smaller on many of their jets. Their weight limit is 26 pounds on British Airways and down to 22 pounds on Veuling Airlines. Keep in mind that if thy have to check your bag because it is too large, you may be assessed a higher than normal luggage fee. It is always a good idea to keep essentials packed in a lighweight day pack inside your carry-on, so that if they have to check it, you can pull out the essentials day pack with your documents and meds and other essentials.
In addition to the carry-on, you will still be allowed a “personal bag” that has to fit under the seat in front of you. It can be a small back-pack, purse, briefcase or computer bag. It should be less than 36″ in length, width and depth. Something like 15x13x8 inches. The personal bag on Southwest is also larger; a maximum of 13.5×18.5×8.5 inches. Check the above links to check personal bag size limits on the other major airlines.
Growing weary of the suitcase issue, especially when travelling in Europe using trains and subways to get around, we switched over to a carry-on bag with built in back pack shoulder straps. So much easier to move around with them. Keep in mind that they come with or without wheels, but you will give up about 15-20% of the space if it has wheels. We purchased eBags backpack carry-on bags. You can also get them from Rick Steves.