Have fun! The last period before the exam will be pretty awful no matter what so it might as well be preceded by really enjoying the subject. That is also the best way to get into a good position - like my umbrella-buddy says, if you are getting involved in class discussions, thinking about the texts a lot and actually enjoying the ideas in them then writing readings will be kind of spontaneous (it always was for me) instead of something you have to labour through.
I would actually avoid professional essays at least until you've developed your own ideas about the texts. My guide: if you don't find yourself yelling in exasperation at how dumb some of the stuff in professional criticism is, you probably haven't gone into the text yourself enough yet.
More specifically, if you're borderline B+/A then the most likely thing you're short on is language analysis (though obviously this is a huge assumption and it may not be - in my experience though, that's the way it goes.) Analysis like you need to do in Lit pretty much doesn't come up in any other subject, it's also one of the most annoying things in Lit. That is the thing you should probably work most on, especially early in the year - the good thing about this is you can practise it even on texts which aren't going to be on the exam or which you don't want to write on. Think about the language, how it's been constructed and how that construction is conveying the deeper ideas of the text. Failing that - at the risk of sounding like a jaded hack - look at the construction and how you might link it to the ideas, even if you think that link is tenuous or not central to the way the idea is coming across. Obviously the first way is better, but the second is usually fine (and often less tenuous than you think)
If as you say you enjoy Lit, you're capable at analysis and good at formulating ideas, then you basically have all the building blocks so it's just a matter of refining. Lit is great fun, make sure you keep enjoying it!