Mystification about the correct placement of words in a sentence is common. We have taken conjunction “not only,” “but also” on our table for study. Look at the following sentence, “Digital camera has not only affected taking photographs, but also our day today life.” Here, “not only”
exhibits that in the further sentence there is going to be some change and other action will take place due to the survival of the digital camera. Over here “affected” is working for both the parts and is an operative verb, hence must be preceded by “not only” and also covered by “also” post conjunction.
“All his good work in the school has not only assisted him score good but also to enhance his abilities gradually.” In this example you can see the misplacement of not only it is inserted forcefully and not used cleverly after the verb phrase has assisted and also in the later part to has been inserted. The proper framing would be “All his good work in the school has assisted him not only score good but also enhance his abilities gradually.”
“I consider him both as a perfectly set example of a person who does all his work carefully but also as a person who takes care of all.” This very example is a mixture of two phrases yet judging against; “both…and” also “not only…but also.” To make it correct you must use either of the two, like: “I consider him both as a perfectly set example of a person who does all his work carefully and as a person who takes care of all” or this way “I consider him not only as a perfectly set example of a person who does all his work carefully but also as a person who takes care of all.”
I would say all the phrases do enhance the beauty of your writing at the same time if it is not put correctly it really messes the entire meaning, so I would suggest you to be very-very simple and easy to sink in the readers mind. To make it fancy we cannot complicate things for them. Correct?