Good point, it’s a great question. It depends on what about your job is the issue(s). Is it the lack of time, is the job tiring, or does it require too much of your attention? Without knowing that it’s difficult to answer and implement solutions.
The point is, just like you go to work everyday between 9 and 5, whatever time you can spare for your blog (or whatever it may be) is dedicated solely for working on that task. If you only have 20 minutes a week to write, treat those 20 minutes as you do your 9–5 job. If you only have time to publish once every other month, do that but stick to that as any other deadline.
In my experience, “treating your blog like a business” is 95% about your mindset. Some can’t afford the premium theme or a custom domain, some are never able to start their own company, and many have other jobs and obligations making it difficult to post every week and stay on schedule.
Although I think the advice are good (and I personally follow them), I don’t think they are the most important. Start with small and realistic goals and whatever time you can spare, dedicate it to your blog/project and that alone.
And just like you should with a regular job, don’t beat yourself up if you slip up and make a mistake. It’s inevitable and completely okay. Pick yourself up and try again.
Hope it makes sense.