The traditional way is go to Google Keyword Planner to get your keyword ideas, but since it updated to force you got an AD campaign or wont show you real number of each keyword you search, you can use "keyword everywhere addon" in Chrome.
Or you try to use some 3rd party keyword analyzing tools to find your dream keywords: for example, longtail PRO, Semrush.com, these awesome tools would save your life.
Better before find a good keyword, know the basic SEO things, read some blogs, books, and then gradually start a blog, good luck to you.