Formatting - Your post need not be a circus. If you are not good with formatting, then stick to a theme that is light and descent in colors and the post layout. If you are good with trying new stuff then use that skill to better express through colors, fonts and layouts. Avoid colors that are dark and fonts that are overtly bright.
Optimize images by mentioning the ALT Text and a short description of the image in your blog post to rank better in Google.
A new blog should not add to the existing noise in the blogosphere. Do something outstanding to get noticed.