Your English is indistinguishable from that of the top 10% of writers or so. I had no reason to believe you are not a native speaker until you linked to your page with photo samples written in Portuguese.
> I had no reason to believe you are not a native speaker
"Now, I decided to give it a shot in another language" and "may I ask you to subscribe to my blog's newsletter or its RSS feed? They are both on site's footer." both read non-native to me; I'd expect a native to say "Now, I've decided..." and "They are both in/on the site's footer".
But I agree with everyone else that rpgbr's English is excellent, more than adequate to publish English-language journalism. It is extremely difficult to get all the details of a foreign language right every time, and in most cases it's not a standard worth reaching or worrying about.
(And if you do worry about it... practice is the best way to get there.)
