I am not terribly controversial, but I think I do okay on Twitter. Thing is...my theory is that you have to be clever, it helps to be nice, and you have to provide content.
Content is not your book. Nobody cares about your book. (This isn't a slam on you or your book--nobody cares about my book either. There are more books than anyone will read in a month of Sundays.) Content is stuff that people WANT to see, fast and easily consumed.
So...for example, I post macro photos of bugs. I am huge with Twitter entomologists. (Hey, they buy books, too!) I talk a lot about gardening. And I don't mean like "These are TEN BRILLIANT GARDENING TIPS" but like "I keep hearing this weird gobbling in the woods and I think the wild turkeys are watching me and this is how I'm going to die." (True story.) I talk about birdwatching. To excess. I liveblog the very weird things that go down in my coffee shop, which have included such delights as the man trying to make a snapping turtle skeleton hat.
I post funny illustrations. This gets you FAR if you have that particular skillset.
I don't know if any of this means people will buy more of my books, but I get @'d a lot from people who've been stung by caterpillars or want to know what a plant or a bird is. I assume these people also buy books, but honestly, I don't care if they do or not--if I can tell them how to soothe the caterpillar sting, it's not a tweet wasted.*
If you can consistently make clever, insightful replies to better connected authors, that is a good thing. If you can't, don't. Failure mode of clever. However...err...try to do it because you have something to say, not because you are steepling your fingers and going "Ahah! Another ten years of this and they will follow me back!"
Signal boost other authors. Ask questions! "How does this work?" will get you farther than lecturing someone on how a thing works. Join in on silly stuff. Talk about your passions.
I don't think it's wise to go into Twitter going "I shall use this to advertise my novel!" It's better to go in saying "I am gonna talk to people! And connect with people!" and then occasionally mention "Oh, hey, got a new novel out this week."
I've only got 6K followers, so take that with a grain of salt. But a surprising number of them buy books. And even if they don't, I have a lot of fun talking to people on Twitter.
If this all sounds horribly daunting, and you don't have time, then Twitter may not be for you. I live on it these days, but some people can't stand it. It's okay if you are not a Twitter type. No shame attaches to you. (I can't do Facebook, myself.)
One caveat--DO NOT tweet at someone and request that they follow back. This is rude. They will follow back if they want to. You asking pretty much guarantees they won't, plus you get to have a horribly awkward conversation about it! (Exception: "Follow for a minute so we can DM" over sensitive information.)
(I shouldn't have to say this, but I had a guy from AW get super weird at me a year or two ago demanding I follow back so that I could hold him accountable for...something? Wordcount, maybe? and would NOT drop it when I said "I only follow people I know well.")
*Scotch tape over the area stung, to pull out the hairs that cause the irritation. You'll probably get a rash and it'll hurt for a few hours, for most caterpillars. If you get stung by a tiny thing that looks like Donald Trump's hairpiece, that's a puss caterpillar and a trip to the doctor may be in order if it gets you good. This is not medical advice, consult a physician, etc.