Affiliate Marketing Secrets

I am a graduate assistant for the promotions director for the television station that is affiliated with the university I attend. Recently I’ve been unconfident in my ability to perform for my boss. It’s not like my work ethic is poor, but I feel as if I make more mistakes then I should.
I want to improve as quickly as I can in an attempt to have a job request close to when I’m finishing my thesis. Also because her future recommendation is crucial to my resume.
I want to talk to my boss privately and ask what my strengths and weaknesses are and how I may improve, but I’m not sure if that’s proper boss-to-worker etiquette. It seems that asking for help would be proper, but I still see the situation being awkward for some reason.
So my question is do you think it would be proper etiquette to approach my boss about how I may improve?
And if so, how I do I not make it sound like a desperate attempt to gain approval?
Please, I only want answers if you can also recommend as to how to go about the situation, or reasons for why I should not proceed.
Thank you in advance.