<boggle>
Second person? I hope you mean third. Second person stories are extremely difficult to bring off and certainly not something a beginner needs to master. It’s hardly ever used. A teacher who insists on using it borders on incompetence.
So, I’ll assume here that you really mean third person. From your description, I don’t have much faith in your teacher’s ability. There aren’t a lot of “rules” to follow for third person. Basically, you need to be aware of the point of view and keep it straight, mostly by making sure that the point of view character in the scene doesn’t know anything he wouldn’t normally know (like what someone else is thinking). But there are exceptions to that – no POV (“camera eye”), all POVs (“omniscient”), switching POV from scene to scene, etc. If you keep the POV straight, 3rd person isn’t all that difficult.
First person is slightly harder, not from a technical sense – you won’t make the mistake of switching to another character’s thoughts – but because of the need to create the narrator as a character. It’s difficult for beginners to avoid the trap of having the narrator be them and it is a bit more difficult to deal with certain aspects. You can’t deal with things the character doesn’t know, for instance. OTOH, if the character does know something, first person is a great way to tell the readers the information they want to know without it seeming like an info dump.*
One trap is that the writer assumes that the reader will take the narrator’s words at face value, but the reader doesn’t always do this.
For instance, suspense is very difficult in the first person, since suspense requires that the reader knows something the narrator does not. However, mystery works well in the first person, since both the reader and the character don’t know what’s going on (very many mysteries seem to be written in the first person).
So it is a bit harder to write in the first person (and this is exacerbated by the fact that people think it’s easier), and a good writing teacher will mention this fact. But to forbid it is poor teaching. How else can a writer learn how to use it? Not from memorizing a bunch of rules, that’s sure.
But ultimately, it’s not a matter of looking up rules. It’s a matter of writing the story. The technical issues will resolve themselves, or they won’t, and the best way to discover what works is to try it out and see. (Especially since any rule can be broken in writing.)
From your description, it might be best to ignore most of what your teacher told you.
*See the Turkey City Lexicon for the definition of this and other important writing terms.