For example I am searching my website with a keyword "apple juice". I believe that the best page of my website for this keyword is www.applejuice.com/apple-juice.html but doing search with this keyword google shows my other page in the results www.applejuice.com/apple-is-a-fruit.html which I believe is not as relative with keyword "apple juice" as www.applejuice.com/apple-juice.html page is. So why google finds the other page and how to make it to find the one which I want it to find?
Perhaps your page www.applejuice. com/apple-is-a-fruit.html is more powerful than first one. Or you build more links for second page than first page.