Time and effort to improve the numbers. That is why we do what we do.
Asking whether your rank and trust scores are good or average depends on what your competitors are doing and where you want to be. If the numbers are better than all of your competitors, then it is a great score. If it is lower than all your competitors than it isn't a good score. Ultimately, you will have a higher likelihood of ranking well with search engines the higher your scores are.
In a nutshell, MozRank means your link popularity score which is measured by the number of quality of links. MozTrust doesn't measure the number of links but the "trust" of the links-which means the higher quality sites that are linking , the higher your trust score is.
Here are more technical details regarding what the specific terms mean and how they are measured if you want more detailed information. I have given you the link for more information and some excerpts that should be helpful:
**http://www.seomoz.org/learn-seo/moztrustMozRank **
"How is MozRank Scored?We calculate this score on a logarithmic scale between 1 and 10. Thus, it's much easier to improve from a MozRank of 3 to 4 than it is to improve from 8 to 9. An "average" MozRank of what most people think of a normal page on the Internet is around 3."
"How can MozRank be improved?A web page's mozRank can be improved by getting lots of links from semi-popular pages or a few links from very popular pages."
http://www.seomoz.org/learn-seo/moztrust
"MozTrust is SEOmoz's global link trust score. It is similar to MozRank but rather than measuring link popularity, it measures link trust. Receiving links from sources which have inherent trust, such as the homepages of major university websites or certain governmental web pages, is a strong trust endorsement."
Bottom line is don't focus on the numbers so much as the activity to help you increase the numbers. With activity and focus comes results. Good luck...