Supposing you have just received a request from editor of a journal asking if you would be eager to review a paper submitted for publication. How should you respond to this offer? Please elaborate !
If you have the right competence, it is important to have good attitude and accept. If you publish regularly yourself, why should others spend time on reviewing your papers if your are unwilling to do reviews for others.
When I was editor of a journal, I realized some people that were pushing for quick reviews of their own papers but responding that they did not have time for such work when I assigned a review to them.
I am checking first if the paper for reviewing is in the range of my expertise. If I am able to review the paper a an expert on the subject, I am accepting the offer to review it, and I am doing it as fast as I can, to save the researcher's ordeal of waiting for a long time for reviewer's decision.
Read and give your opinion-as simple as that! A colleague or somebody I do not know-does not matter. What matters is the content and whether the people who are going to read it are not going to be misinformed, misled. whether the paper is somebody's else. Whether it is enlightening or not? And finally how strong the process of argumentation is? Truth is relative but the process is very precise and may help the reader sharpen or develop his/her own.