I bought a website for blog and its keyword is postcardideas. Sub keywords in articles are "funny postcards" or "business postcards" etc. Main keyword gets 10k monthly searches and 600k total results. Sub keywords get 1-10k month and 500k-10 million results. Is it a problem that my main keyword is not connected wholly to sub keywords and are the sub keywords too generic. Am i competing against "postcards"? Aiming to write many articles to reach at least 50 dollars a day some day..