With everyone blogging these days, you really need a blog post idea which makes you unique and attract lots of followers. There are so many ideas to choose from. But the best blog idea comes when you find your unique voice. Dig deep within yourself and write from your heart. It'll reflect in your writing and your readers will find you authentic. Who does not love a person like that?
In my writing class, we were taught it's best to write what you know. The same applies to your blog. Use a blog post idea that stems from your personal experiences. The best idea should be custom tailored to your daily life. For example, if you're an avid gardener, write about what's growing in your patch, how you planted, what seeds you used, how many times you water the plants and so forth. Take photos of your plants to show your readers.
If your blog is about the town you live in, and then write about the place you visited over a weekend and add the photos to show the readers. That way you're writing from your personal experience of gardening and traveling respectively. It'll show your readers 'you walk your blog'. Nothing is more annoying than a person who blogs about stuff they've no idea about eg writing about cooking gourmet meals when they can not even boil an egg.
And when you blog, write just as would speak if you were face to face with your readers. If you use formal language, which you severely speak, you'll come across as stiff and boring and you'll fail to establish a relationship with your readers. But there are some things which are a no-no like using expletives. No need to turn your readers off. Simply write about what you know, whether it's an event that happened or advice you can give based on your life experience. Keep the language clean, simple and just as you speak everyday. That way, your blog post idea keeps your readers hooked.