First of all, you should be very good in your English writing because it is an international language and is understood by most of the people around the world. If you are not good in English writing, you can take different courses which are provided by the training institutes or you can simply learn it with the help of books in your home. Besides, you can also take online classes to improve your English writing skills.
There is quite a difference in British and American English regarding the spellings and pronunciations of the words. Therefore, it is very important for you to decide which style of English language you want to follow for which you will have to know your audience.
If your audience is more diversified, you should also keep options for more languages. For instance, you can publish your articles in Italian, Spanish, German and French in order to attract more people towards your blog.
You should know the culture of your audience so as to make your articles more interactive for them. You can get the knowledge of the culture of your audience by watching international movies, reading different books or you can search it on the internet.
You have to be very friendly in your writing and should never criticise any part of any norm of a particular group of people so as to develop a good relationship with everyone. Besides, you have to be well aware of the slangs which are used in a particular region of the world.
It is very important for you to post your articles on a time at which you can bring maximum audience towards your blog.