Remember, Quality, over Quantity a blog does not have to have 10 paragraphs to be a good blog, If you look at this, you can see it only has a paragraph, and then the coding to add in the javascript.

Have a Good Topic

Im sure staff wont highlight a blog about ponies, they will most likely highlight a blog that will HELP users, opposed to your thoughts, and opinions.

Has it already been done?

If you want to do a blog about "How to edit easier on Wikia" check and see if it has been done, if not then I am certain you will have a higher chance of getting a blog highlighted.

Final Statements

So in conclusion, you don't need a lengthy blog, just be original and have a good topic. =D