I've been getting this question a lot. Newbies are afraid to join Because they don't know what kind of blog they would have.

This is a hard question because the Steemit community isn't as big as Reddit, or Facebook.
But at the same time, it's easy to answer.

What do you love?

It's obvious, you should write about what you enjoy and what you love.
While some subjects obviously do a lot better than others on Steemit, You have a chance to "dominate" certain niches with your writing; You'll be ahead of the game. And later on, you'll be more profitable.
So this is a good long-term strategy.
So what is a short term strategy, If you want to build up your Steem Power Now?

Write About What You Like.

This may not apply to everyone. If you LOVE Cryptocurrency, Then writing about what you love is a great short term goal for you and a great long term goal. But if you LOVE to teach Painting, Sometimes painting posts won't do as well as other posts. So if you LIKE art, You can go for more of broad niche while the Steemit community is small.
Then as the Steemit community grows, You can make yourself stick out by going deeper into the topic.

Should you jump around subjects?

As you can see, I jump around a ton! I write a little bit about everything, Self-improvement, finance, Minimalism, Art, Some journal-like entries.
There are benefits to this, But there are also "cons".

The benefits!

You'll reach a larger audience!
You'll be able to relate to more people.
You can determine what works for you, And what doesn't.

The Cons

Getting "authority" over one niche later on will be difficult. People won't know where you stand.
Your followers will be spread out over a variety of subjects instead of being passionate about one specific subject. Which once you go for a specific niche, You may lose some followers as a result.
People may be somewhat reluctant to follow you, If they don't like the bulk of your topics. They are more likely to be "Surprised" about what you write, Where as if you write about the same thing all the time, They'll be accustomed to it.

Something for you to decide!

For those of you afraid to get started, Just do it. Don't expect your first post to be perfect. If you look back at some of my first posts, They sucked LOL! I was originally going to write nothing but Adult Coloring posts, But not a lot of people who enjoyed coloring were even here! Also that got boring for me real quick.

Make Steemit Goals

Just like everything else in life, You need to make goals. How big do you want to grow your blog? What type of audience? Will you try to respond to all comments? How will you use your upvotes?
Will you spend your money as you go, Or try and build up your power on the platform?
There is no right or wrong way of doing it. There are a lot of people who do a variety of methods with great success here.