Content is king when blogging. Even more specific, repeat content is king when blogging. Blogging is much more work than most people realize since it requires continuous creation of content. As such, I strongly recommend creating a pretty good sized batch of content prior to official launch of your blog.
It depends on what you want to do, but I would recommend at least creating 10 full, quality articles prior to launch. If you’re a big time planner, you may even consider writing up to 50 articles pre-launch.
Writing this many articles ahead of time will allow you to follow through with a successful launch. Depending on your objectives, your consistency will vary, but many blogs attempt to publish new, unique content every single day. This frequency certainly helps get your blog off the ground and begin to bring in traffic.
Having a set schedule of to-be-published articles allows you a buffer to keep creating articles and ramp up your blog while always having several days or weeks of articles in place to be published. By adding to the queue of to-be-published articles, you can keep the buffer going which is very helpful in case you run into a time where you can’t sit down and write new content.