[ellisv]

> I want to start writing a technical blog (related to computer science and development)

Why?

> but almost every topic I think of has been written upon by someone, probably better that what/how I would have written it.

So?

If you want to write the most authoritative blog post on some technical topic, why? Why be the best? Why that topic?

Write what you want to write about. In a year or two you can look back and revise/delete your old posts if you want. Do you think your favorite blogger's first post was amazing? Probably not.