(non-native english speaker, be kind) I'm not even a good code reviewer but I think I can share some insights:
1 - First of all remember these two things: "There is no perfect code" and "There is a human, who doesn't know everything, on the other side".
2 - Understand the scope of the Code. What is this piece trying to achieve?
3 - Read. Calmly.
4 - Read. Calmly. Again. Reading code is hard and takes practice.
5 - If you think something could be done better but it is not required, open the discussion, not everything is a 'change request'.
6 - If you don't understand something, ask.
7 - It's a team play.
8 - Praise what needs to be praised.
9 - Read the tests, for god sake. Try to think test cases that the PR didn't cover.
10 - Understand the moment that the project is. Sometimes some changes are too big for this review. If this is the case, could it be done later?
I know these are pretty simple insights, and no real technique, but they are often forgotten :/
(Brazilian here with bad english) There isn't much interest yet. But that is expected.
Information flows somewhat like this here: First they ignore it hard, then media comes and make a fuss and that makes the gov. officials respond with disdain or support (depends on the strategy they adopt). But if it gets hotter something bigger magically happens to distract public opinion.
At least it is already on dados.gov.br, which is the brazilian portal for open data, meaning at least received some support from groups inside the government. But almost no interest from conventional media.