keyphrase

"So, i am writing an article that is about 3500 words , i am confuse about, KEYWORD DENSITY ON MAIN KEYWORD ( contain 4 words) example : "car parking in Vienna" what shoud be the appropriate kd for it". What should i do ? shall i try to make the keyphrase density around 2-3%, if i do that car...

What does everyone think about the Yoast keyword/keyphrase density tool and what it says about putting keywords in titles? Is there something better or just researching a high ranking blog post is best? I would love to hear your opinion.