The phrase "goodly portion" refers to a significant or large amount of something. It suggests that there is a generous or substantial quantity of a particular thing. Full definition
Tom: And Bush alienated the other half, alsong with a goodly portion of the world. (religion.blogs.cnn.com)
«The town board is going to engage an attorney cognizant of water issues, to look at the 1929 decisions [that govern Woodstock's relationship with the city of Kingston, which owns Cooper Lake and a goodly portion of its watershed, utilizing the water for its citizens] and making sure our understanding of them and the DEC's coincide... let's get on the same page and get some modern language.» (hudsonvalleyone.com)
In addition to straightforward expertise, you also need a goodly portion of intuition and creativity for it. (sciencedaily.com)