Basically, if you’re a human acting from a genuine interest in the blog or its contents (haha what), I’ll get your comment approved even if it gets marked as spam, and probably even if it’s a “nothing post”.
If you’re promoting your own blog, you need to make a relevant comment. That’s all. It shouldn’t be too hard in theory, but some people do not bother reading your posts at all. Obviously, that doesn’t apply to you, as you’re reading this now. Just bear it in mind.
Also, although I don’t require that your comments are incredible, rambly incoherent messes will reflect poorly on your own blog, making people less likely to click through from my site.
If you’re a human acting on behalf of a company, I understand completely that you need to get your company out there. However, I’m not going to approve comments that are completely devoid of content or unrelated to the blog. Keep them relevant, but also as well-written as possible. As long as you follow these rules, I don’t mind if you use anchor text in your post.
If you’re using bots, I’ll only approve your comment if it coincides with a perverse whim. These happen increasingly rarely.