Changing file permissions – Not like all the other questions

I know that this is a topic that has alot of posts, but i want to learn this differently. Please guide me.

Knowledge that i have:

• I do know how to change file permissions in Filezilla
• I do know what the File permission modes like 0400, 0477, 0677 mean

Knowledge that i don’t have?

• What permission modes to set for which folder or files?
• When should i apply a certain permission mode and how to decide if i need to set the same permission attrributes to the files within a directory or above the directory?

Why i’m asking this?

I got this error:

Unable to create directory /home/httpd/vhosts/arenabadminton.com.my/httpdocs/wp-content/uploads/2009/01. Is its parent directory writable by the server?

Now i now that the case here is i cannot upload files to the uploads folder. Looking at the server setup via filezilla, i can see that i have the folder “uploads”

/httpdocs/wp-content/uploads

Now how do i decide on what file permission mode to give to which directory of file in the httpdocs folder?

Please guide me. I’m asking this because if in the future i use another feature in wordpress and it says that i need to have permission to edit/read/write/upload a certain file, i’ll know exactly where to change things and i won’t have to post repeated questions here.

Really appreciate all the help,
Cheers!
Jaysone