Everybody should vary the keywords in the article. And density should be 2%. Note please, everything natural is a must
I always keep 1 targeted keyword, and maybe about 5 sub keywords for all articles I write. It seems to work for me. Google will look at your actual content, so it's important to optimize your content for people, and not for the search engine itself. The keywords are just for targeting triggers in search among other things (Which Google dislikes too many uses of keywords). Google said it best when they say "Optimize for people, not for search engines" or something along those lines.
A good way to subscribe a bulk of traffic is through video marketing & web 2.0 sites. They help me a lot to drive visitors to my site in a perfect way.I mostly look in this way, if traffic is higher, doesnt matters, whats the conversion rate, that matters a lot....Giving your traffic something when they come to your site is one of the important things I found, dont let them leave your site for long & give them something to remember you !!!
Generally i would keep the percentage of keyword / total content about less than 2%. Also, in this post Panda age, i would try to diversify my keywords with synonyms and other relevant keywords.
keyword density should be around 2%...usually ! but now, maybe you need to catch up on some keywords, so you can make 4-5% let's say, but more than that and google will get suspicious. as for links, in my opnion 2 it's best, looks more natural...but the again, depends on your needs and how much risk are you willing to take, cuz you can put even 5-6 links if you want...
Having your keyword repeated to 2 to 3 times in a 500-600 word article is just enough. It's way below the 2 percent margin, and it also looks more natural.
If you are referring to articles posted outside the side, I suggest you read the terms and conditions of the specific article hosting site. Each site will have its own criteria for approving an article with links. Some don't allow links in the first para, while others allow links only in the author's box. You can check out this page for more insights on your LSI query: http://lsikeywords.com/. If you run a business and wish to do SEO in a professional, and systematic manner, I suggest you get in touch with a good online marketing agency for SEO and a creative ad agency for designing. Sasikumar Sabre Marketing Services Pvt Ltd Bangalore
According to new updates in google about stuffing keywords, you should only use 2-3 keywords per article.