For promoting a blog post, it can be promoted successfully with the help of social media.

Hi,
one simple question concerning blogs. Is it better to start a blog integrated with my shop or create it outside of it (on blogger by Google for example)?

You can share your blog post in social media platforms. Make sure your content is interesting to read and attract user to come back again to visit your blog.
Use attractive and related images for every blog post and use interesting, unique, fresh and trendy content for your blog.

You need to make posts on regular basis with high quality SEO link-building.

Arrange quality Relevent links
 

You can enhance your rankings arranging quality back-links .
You can see others people website link using tools like backlinkwatch or seoprofiler