First, you need to get the Blogger's api-key. login to code.google.com/apis/console and choose Services, then click Blogger API v3 request access. Fill out the request form. Wait until you get the api-key. Once you get the reply email and if Google grant you the API Key, then go back to Google APIs Console, follow the activate instruction in the email. After you activate the service, you will find the API Key in the API Access.
Use python-requests to fetch the data from your blog would be very easy. You can find my implementation on fan-zhang.appspot.com/blog.
Looks like every time when you create the blog, the blogID will show up at the address bar. However, once you publish the blog, the blogID disappear.
How to find blogID after it's published?
I think the easiest way is go to the dashboard and then click Posts, choose the blog you want to get its ID, click Edit. The blogID will show up at the address bar.