A good profile firstly: your profile picture, bio, banner all need to be designed to draw people from your niche in and give them an idea of what to expect. Then, your pinned tweet should also have some good info in it or at least give more insight to the account for viewers.
At first you won't be getting many followers at all, so tweeting is fine but kind of pointless. Instead, find big accounts in your niche and reply to their tweets, a good way to do it is by "adding on" to what they have to say. If you are early and consistent, then you will gain followers slowly over time.
After that, find accounts similar to your size who do the same thing, and offer to boost eachothers posts by replying/liking/rting, do this with at least 30-50 accounts and you have a much bigger audience.
You can then get all of these people into a group chat where they will all retweet/like/reply to every members tweets when they make one. This is how some of the biggest accounts do it, I was in a gc like this which was dominated by 100-200k follower accounts.
You should also by this time try to get the bigger accounts in your niche down to take part in the group, as you will have a bigger audience so steady growth and should reach higher numbers very soon.
When you tweet, make sure it doesn't contain a link or a @ mention of someones username or less people will see it, try to include a topic name in the tweet that you want to trend for if it's possible, and media is even better.
There is also the obvious way of getting into arguments for engagement, but that isn't good for long term and even isn't the best idea for short term.
