You are making a website, each page needs to be structured for best SEO practices. As you are writing content you must have already done your keyword research. You must use these keywords throughout the page in just the right amount. Too many keywords is bad. Not enough keywords is also bad. I would suggest reading up on how to properly structure a page for your site so you can achieve maximum optimization. Once you get the hang of it you will find it is not too difficult. And the benefits are going to pay for themselves for a long time to come. Then there are the long tail keywords. You also will have to figure out when and where to use these keywords. There is a time and place for them but not necessarily on the first publish of your page or pages. It seems it is easier to rank a site if you first concentrate on just the main keywords. Once you are ranking well for those then you can go back and add in the long tail keywords. I recommend reading up on this subject before you attempt to write content for your site. Making mistakes are costly and time consuming. I know I have been through it all before.