How to come to know that you have done some thing non-trivial in the research?
In a recent project I felt that I had somewhat trivial results, and that I needed to add more to it before writing the paper. The new steps turned out to be so non-trivial, and take so long time, that I decided to write up what I had in the meantime. By putting the work so far in the form of a proper paper - you know, with an introduction that attempts to convince others that the work is interesting and worthwhile - I ended up convincing myself that the results were non-trivial and made for a good paper already.

In hindsight I had worked on related stuff long enough that my results seemed less novel to me than they would to another person. So, my advice is to write it up, and trust your supervisor.