I always bring a couple days of clothing in my carry on, just incase my checked bag goes missing (this happens more often then you think). I select my favorite pieces of clothing (items I would be devastated if anything ever happened to them) and pack them in a compression bag at the bottom of my carry on.
I use a 20" wide-body spinner that fits easily into the overhead bin. I also use a tote (as my personal item) that attaches to the handle of my spinner, for easy maneuvering in the airport. I place the items I want to use during flight in my tote, since it can slide under the seat in front of me. I think it is so annoying when people slowdown the boarding process by unpacking their suitcase before sitting down. Think about what you will need during the flight and come prepared!
Finally, here is a checklist so you don't forget anything: