For many college students the beginning of learning how to write well is to unlearn much of what they've been taught.
Most students arrive at college with a grab-bag of rules that they try their best to adhere to.
There are also lots of idiosyncratic usage edicts. Some teachers for instance require their students to dutifully change towards into toward every time they come across it. Now there is a grain of truth and even more in many language and usage rules. It's true, for instance, that one should be careful about using split infinitives , simply because most readers have been trained to recognize them as a mistake. But that's not the same thing as saying one should never split an infinitive, or that split infinitives violate some real law of language.