Decide on a basic topic for your sentence.
Determine the subject (noun) of your sentence (example: girl).
Choose the action (verb) of your sentence (example: read).
Pick the object (noun) of your sentence (example: book).
Combine the subject, verb and object into a simple sentence (example: The girl read a book).
Choose a detail to describe the subject of your sentence (examples: young, bored, clever).
Insert this detail (the subject's modifier) in front of the subject in the sentence (example: The young girl read a book.).
Select a detail to describe the object of your sentence (examples: her, long, frightening).
Insert this detail (the object's modifier) in front of the object in the sentence (example: The young girl read her book.).
Modify the subject and/or the object with more than one detail, if this adds further clarity to the sentence (example: The young girl read her long book.).