I have been doing the carry-on only for the last 5 years.

It is all about making compromises and learning what you
can and cannot do without. It also feels good to not be
burdened by unnecessary luggage.

It also is not about breaking the rules but learning to live
within them and being respectful of fellow passengers.

How do you start?

1) Pick a bag that is carry-on legal for the airlines you
will be flying.

2) Sort out your items to fit the above bag, preferably
not stuffed to the gills such that you need to put it in
a vice to close the zippers.

It can be challenging but also fun to really scrutinize
what you bring with you.