Make sure to learn ALL principle parts for vocab in the RVL (restricted vocab list- you need to learn this English to Latin). In our school we've been given a a bit of vocab to learn each week. We then have a test on it and we get a mark out of twenty for our first principle parts- basically just identifying which word they mean- and then a 'level' (platinum, gold, silver, bronze) for how good your principle parts are. It's really useful because learning vocab in bite size chunks is really helpful.
A lot of people tend to rest a little with the DVL (defined vocab list- you need to learn this Latin to English), however it is still super important to learn principle parts here too because, at the end of the day, in a translation any principle part of the word can come up. Once we finished the RVL we also had tests on the DVL where we could basically be given any conjugation of any tense or any type of participle for each word, which again is helpful because that's what it's going to be like in an exam.
As far as grammar is concerned just make sure to cement those basic principles in your head with cases, tenses, moods and participles, because they are essentially the foundation of grammar. Syntax can be a headache because there are quite a few constructions, but just make sure to keep going over them.
I actually haven't done a GREAT deal of literature (since I've just finished year 10 and we do most of it next year), but one key thing is that you need to know what each individual Latin word means. My teacher told us this amazing story about him being in Y10, just learning the translation off by heart but not actually looking at the Latin, and absolutely flunking a test that he had on it, since he didn't actually know which part of the translation he was looking at! Learning the Latin and English side by side will both help you know the individual Latin words, but I think it also helps you to learn the translation quicker since the Latin aids you.