When should I use a comma before a prepositional phrase?

Question

Can someone please give me some examples of when I should and should not use a comma before a prepositional phrase?

These are some of the sentences that I am having trouble with:

1. These are the problems that I've struggled with in my own life

2. I looked on the other side of me & seen a bird.

3. All of my friends came with me except Ron.

4. I want to help all of the people who have problems like I've had before.

Can someone show me which sentences need commas? I need someone to show me where the commas need to go too!

Answer 1

None of your examples needs a comma before the preposition. All of the following would be nonsense:

2. I looked, on the other side of me and seen a bird.
   I looked on the other side, of me and seen a bird.
   I looked, on the other side, of me and seen a bird.

3. All, of my friends came with me except Ron.
   All of my friends came, with me except Ron. All, of my friends came, with me except Ron.

4. I want to help all, of the people who have problems like I've had before.

The only possible commas I could see (and they would be optional) are:

1. These are the problems that I've struggled with, in my own life.

3. All of my friends came with me, except Ron.

They are optional because they serve as a pause before a parenthetical expression.