I'll skip all the BS and just ask the question straight up. How do you use words that end in -ly? Do you use them as little as possible or sprinkle them about in your story to add flare?

I ask this because I've come across different tutorials that talk about their use. Some say to not use them at all, while others say to use them but to be cautious with their use as overuse can be the sign of a poor/amateur writer.

It does add flare, but like a flame, too much can be dangerous. Try using them to grab the reader's attention, but not so much as to make them confused, because then they lose interest.

Something my English teacher once said: "It's not the nouns and adjectives that make a story good, it's the verbs and adverbs". I assume you mean adverbs (words describing actions) in the OP, right?