Google and other major search engines are against keyword stuffing. So what are the new guidelines to focus on keywords while writing content?
What should be the ideal keyword density?
There is no such thing as ideal keyword density, and there never has been. Even at its most primitive, Google's algorithm wasn't so stupid as to be fooled by people who used a particular word exactly 3.6% of the time, or any such artificial number.
Just write naturally, and make sure that it reads well. If it sounds spammy, it is spammy and you need to rein back on how many times you use the same words and phrases. If it doesn't mean anything to people who are not familiar with it, you probably need to use those terms a little bit more.
Useful video from Googles Matt Cutts on "keyword density", worth watching http://www.youtube.com/watch?v=Rk4qgQdp2UA
Write natural content, for people, not for machines. I'm sure such content will contain the "ideal" keyword density
Ideal keyword density should be 2-3 % . If you do keyword stuffing you will be penalised so use your keywords wisely. Use keywords in your image alt tags, in Title tags, Header tags, achor text...This should help your organic traffic
Read what Stevie D wrote earlier in this thread: There is no such thing as ideal keyword density, and never has been.
Instead of trying to doctor your content to meet some abitrary figure, focus on improving the quality of your writing for the benefit of your target audience.