In addition, I will be posting some resources that I have. I've collected a huge number of Latin resources in the past month or so since I'm trying to achieve fluency, so here's what I've got. A good blog post I read when I was looking for resources online was this one:
tl;dr The best way to understand Latin is through the natural learning method, by reading, writing, hearing, and speaking Latin. He also mentions ancient Greek if you're interested.
He recommends reading Adler as a supplement to Lingua Latina since Adler includes additional reading and writing experience along with lessons in grammar in English. Depending on how comfortable you are with the grammar sections in Lingua Latina, this might not be necessary. For listening practice there are a number of them online now, most for free. He recommends the Latinum podcast recordings of all of Adler, but personally I don't find them to be that great. The book itself is sufficient. Instead, I use the audio recordings for Lingua Latina. Read a chapter, answer the questions, check them with the answer key, listen to the audio while reading the chapter again, and then listen to the audio without looking at the book. That's how I use Lingua Latina. I'll post first all the audio recordings from Lingua Latina, then the Lingua Latina PDFs I have, and then some other PDFs, audio recordings, and links.