The Blog Umbrella is great for beginner and intermediate bloggers alike.
For beginners, it can help encouraging brainstorming ideas.
For intermediate bloggers, it can help solidify all your topics & subtopics so you're clear on the direction of your site.
Download the blog umbrella (topic ideas sheet) and start brainstorming possible writing categories, subtopics for those categories and a blog name that fits them all.
If you haven't chosen a name yet and are still stuck on that step, I recommend choosing your given name or a variation of your name/nickname (example: "JessicaSmith.com” or "TipsFromJessica.com”). Remember, you don't want to stall too much on this step and never start a blog because of it.