Even though most airlines say that you can have 2 carry ons, I have been on a number of flights that make you check one at the gate... UNLESS you are flying first class. So, be prepared to have one of them checked :wink: These you pick up on the tarmac or in the unloading area immediately following disembarking.
I have a small suitcase on wheels that fits in the overhead, and I carry a second one for my purse, book, sweater/jacket, and travel pillow.
I advise a zipper on your bag that will go under the seat in front of you... I had one that didn't, and had things falling out of it and that really irritates the flight attendants.
Maybe put out all of the items you are going to want to carry in it, and see what size YOU will need it to be :D:D:D