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.
Stay simple and be original, have patience and perseverance and connect with other bloggers to grow as a blogger!
After completing your post, read it with a fresh eye from the perspective of a reader to check if you enjoy it or if it needs changes.