The best keywords to use on your website for organic SEO are the highly searched for ones
. Often, the most searched for will be the most competitive as well. Try to find highly searched for keywords that are fairly competitive but not impossible. Use these keywords in your on-page SEO your page titles, descriptions and header tags. Choose a couple of keywords for each page on your website. Try to stick to one or two keywords per page to keep it as relevant as possible.
I hope these pointers have been helpful in starting your keyword research. It is something you should take time over and do thoroughly you don't want to be missing out on potential traffic to your website.