I believe it’s important to speak your mine but when you appear to be complaining about everything nobody will take you seriously when serious matters actually occur. The key is how to make your opinions truly effect change without always appearing negative. It is truly not how you feel but how you express it that matters. Here are a few tips (below) that might be helpful.
(1) Start Positive even it appears that there is nothing nice to say find something (ex great effort, nice teeth,).
(2) Pose your criticism as a question. Do you think it might have worked better if? Just curious how do you think this would look?
(3) Accept that they may not agree … initially but your questions might make them think differently sooner then they think.
(4) When they come away to your way of thinking compliment them on their unique perspective on this issue.