Professionalism is something that is, year after year becoming more real, as a career aproaches and I do more and more to make that happen it is important to have some things put in to consideration. Not just with peers, but with everyone, that way it will be a natural thing despite whom you are talking to.
In my view, the basics of professionalism is education, to be the most polite person I can be, to not fail with compromise and work, ofcourse everyone makes mistakes and some things might not even be in our power, but it is our responsability to let other people know if we are going to be late, or had a problem and can’t make it in time. All these things count for professionalism as well as being friendly. It doesn’t hurt to help out a collegue in need or give them some advice – being a good person counts as professionalism in my opinion.