After pondering your question overnight here is my two penneth. Personally I think you could employ someone to teach and critique your approach to structuring lyrics, but your own voice ought to be the one which takes charge in your work. If you have talent it will show through and you'll find your audience. There are countless sites which provide the framework for building whole sets of lyrics and they outline many of the various approaches to structure, but what comes from your gut ought hold your greatest conviction. You can be taught metrical writing skills and you can be taught how to put a set of ideas across in a concise way with natural sounding rhyming, but no one can teach you personal life experience, dreams/aspirations which are the basis on which many a great song has evolved. Yes it's human nature in those of us that are driven to seek means by which we can be better at our pursuits. You may have quirks in your writing style which are at odds with a potential mentor, it's the audience who will ultimately decide if your lyrical approach connects with them. With many songs it's the concept that's brilliant and the vehicle that carries it can be tuned and polished so it delivers that initial concept in style. In summary I think you need to be more specific about what aspects of your writing you'd like to improve upon, you obviously feel there are aspects that could be better or you wouldn't be asking the question. There are some clever people on this site who would most likely offer you some feedback, which would be varied which is very important as tastes vary so vital to get a broader opinion. Perhaps it's your confidence that needs working on because intent will lead to a decent execution if an individual has it in sufficient quantity.
all the best
Tim