To avoid being forced checked I travel with a slightly smaller carry-on bag. In my experience they usually focus on those that are at the maximum limits.

To avoid the risk of being separated from essential items such as medicines, computer, phone, passport, etc. they are carried in my personal item. I use a small vertical messenger bag that is well within the acceptable dimensions for all airlines. It easily fits under the seat ahead of me or in the seat pocket so can be quickly grabbed in the event of an evacuation.