Well, I am also a beginner in blogging. But if you want suggestions I can help. As your profile says, you are a javascript developer. So you can start writing blogs on any concept in Javascript which was once difficult for you to understand. Writing this type of blogs will force you to study the topic in depth in order to present a proper & lucid explanation.
You can also start writing blogs on tutorials of some software to get started or may want to share your journey so far.
Remember you have to keep thinking about the topic and accumulate resources to write the blog.
Most importantly, don't try to complete a significantly large blog in one day. This can be stressful and would be considered as a bad practice. Always try to have a draft which you can work on over time.
Try to Break the topic in small parts & prepare them accordingly.
Over time you'll get used to it. So go ahead and write your first blog Muhammad Wasif Malik !