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.
Originality - Focus more on the originality of content and on a consistent basis. It is a habit you will need to cultivate.
Share your personal experiences on your blog occasionally. It makes your posts more real and helps your readers connect with you.