While there are many styles of writing (some of which may be better adapted to your startup or industry), I've outline the 3 main ones I've used:

1) Write up reviews of your own product

Agreed, it may appear sneaky at first. Yet at the end of the day, small blog owners are happy for content about a thoroughly reviewed product they can post. It is therefore key to market it as a review post coming from a blogger (you) and not as a marketing effort to praise your work. Exchange value for value! I have done about 60 review posts about our own product.

2) Write round-up tool posts where one product is yours.

This is a great way totarget bigger blogs and most don't mind if you put yours in if it fits the space. In my case that was "10 Twitter Tools to Boost Productivity" kind of posts.

3) Write posts that promote the space your product is in.

Now, oftentimes you can't market your own product. So write about the problems your product solves. This is also great as you make yourself a name as an expert for the niche area. In my case that was posts like How To Build Your Twitter Tribe.