A prepositional phrase adds descriptive information to a sentence. The prepositional phrase tells the location or position of an object or a person. It is important to be sure that the prepositional phrase is close to the person or object that is being talked about.
Look at this sentence: A letter came in the mail today from my mom.
The sentence has two prepositional phrases. The phrase in the mail tells where the letter came, so that part of the sentence works just fine. However, the phrase from my mom actually tells about the letter – yet the phrase is placed at the very end of the sentence. The sentence works better if the phrase from my mom is located closer to letter – the noun that the phrase is modifying.
A better sentence: A letter from my mom came in the mail today.
Here is another sentence example: A man is running through my yard with a rake.
This sentence also has two prepositional phrases. The phrase through my yard tells where the man is running, so that phrase is placed correctly in the sentence. However, the phrase with a rake tells more about the man. That phrase should be placed next to the noun it is modifying.
A better sentence: A man with a rake is running through my yard.
When using prepositional phrases, try to place the phrase as close as possible to the noun that is modified by the phrase.