Portfolio Assignment

So last night ater I made all my revisions and tried and made sure my papers were up to par for the portfolio I realize that I then had to type up a 3 page paper telling them why I made the revisions I did and tell my strenghts and weaknesses of my writing. This assignment was pretty difficult and challenged me pretty well. All year I thought I was writing solid essays that met the criteria for an A paper...............boy was I wrong. My highest grade on all 3 of the papers was a 75 and its the paper that I spent the most time on and was the most serious and the one I most cared about. On the object essay I got a 69m, which again I thought was pretty low for all the work I put into. On the ad paper which is the one that I really thought I understood the most and could do a really good job and fill it with awesome detail and overall have a pretty solid paper..............wrong again I got a 52. So I guess I need to stop thinking that Im doing good on these papers and stop thinking I understand the material. So maybe if I have the mind set that I dont know what Im doing that will get me a higher grade. Overall I was pretty disappointed with my grading.