So full disclosure, I’m in the process of trying to launch a personal blog, too (but not about Bordeaux, I promise!). I should also disclose that I’m a digital journalist and have launched and edited about a dozen successful news blogs. It’s a totally different beast when you already have a large audience and a brand attached, so I’m glad you started this thread, as I’m treading these waters, too.
My best advice is what I needed to give to myself years ago: Don’t over think it, just dive in, start writing about what interests you and as everyone has said, have fun with it.
I think having a particular focus or niche is really important! It might limit your audience, which is not always a bad thing. A small audience of quality/influential people, who keep coming back to the blog, can sometimes drive results (depending on what your goals are) faster than random clicks by a bigger group of people who randomly find your blog for different reasons and move on.
Every post doesn’t have to be a long well-researched article – they can be short bursts of inspiration, or a comment on a news story, or a quick recommendation of something you’ve tried. If you’re traveling, post a few photos and let readers know there will be a longer post about your trip when you return. The key (and hardest part of blogging) is consistently writing – whether it’s daily, every other day, or weekly. Posting once or twice and then waiting a month to post again won’t necessarily keep bringing people back to the blog.
Self-promotion is important, so utilize social networks like Twitter and Facebook to send out links – don’t just say “come read my blog” – give them a factoid or make a statement with an interesting point of view that will encourage folks to click. Tag people you write about in your posts so it might encourage them to respond or share your post. Also, have conversations with your readers! If they comment on something or ask a question, respond (nicely) to them. Blogging is more about having a conversation with your readers, than just writing into the ether and hoping someone will read it.
Good luck! I see some great advice in this thread already!