AP Style
Dates
March-July are never abbreviated.
Aug. through Feb. are abbreviated when used with dates
You do not abbreviate months if you are not writing a specific date.
Ages are always written as the numeral
Numbers
One through nine are spelled out, 10 and up are written/typed as the number.
Example: Ben has over 20 video games.
Films, Books, Songs are all "Title"
Percentages
Written as number then "percent".
Example: Gas prices lowered 12 percent.