If you can find popular but low competition keywords, that's great. But these will be very hard to find nowadays. So don't stress if you can't. Even if there's a lot of competition for a keyword, if it's appropriate, then it's worth using. Once you've got your main keyword, use it in the domain name. You can then choose other keywords to target on each of your pages. Most SEO gurus say that you should target 1 to 3 keywords per page. Just make the pages relevant, informative and clear. And about 450 words is a good length.
1.Internet Marketing
2.Email Broadcasting
3.Social Media Optimization
4.Social Bookmarking Services
1.Internet Marketing
2.Email Broadcasting
3.Social Media Optimization
4.Social Bookmarking Services