HOW DO I do keyword research for my newly establish blog?

This is just one method to start keyword research.

Adwords has a nice feature, it will analyze any website and tell you what Google thinks that site is targeting. 

Step 1

Open a Google Adwords account, they're free.  

Step 2

Analyze a competitor's website in your niche.

It will provide you with :

A list of keywords that site is competing for.

How much traffic a particular word or phrase is likely to bring to your site.

It will tell you how competitive the word or phrase is.

And much much more.

When you learn how to use Adwords research features you will find it is not just for Adwords. 

You can do keyword research for your newly established blog by,

1. Identify Keyword Opportunities. Before you can target anything, you need to determine what keyword phrases are likely to bring in relevant traffic. ...
2. Narrow Down Your Topic. ...
3. Write and Optimize Your Post.

Before you begin to write a blog, keyword research can be done by using a free Google tool called as Keyword Planner. 

You can enter a word relating to the theme of your blog and you would get a list of words that could bring considerable traffic, if used. You can use some of the medium or high search volume keywords and include them in your blog. 

If you have already written a blog, you could have a look at your competitors to see what keywords they have used. These are called as opportunity keywords. Hope this helps a bit!