Fairy Tail OC Advice

Soo, this mainly applies to Fairy Tail OCs. However, these tips can be used for any OC, regardless of the anime. I've kind of created this because I DO enjoy reading Fairy Tail OC stories, but I occasionally tend to lose interest in the plot or the character. Please don't take any offense from this. If you write because you want reads, I'm merely trying to help you with entertaining your readers. Please keep in mind, this is entirely based off a group of the opinions of people I know and the opinions I've formed on my own. Just remember, I'm only trying to give help.
Thank you!! ^^