First person narrating is reader friendly. It makes you connect with the main-character, like you're his/her best friend. When used correctly, it's an excellent way of sucking your character into your book.
It has the potential of being a writer and a reader's best friend, but it also has a way of being a writer's downfall, as well as a reader's torture.
1. Make it unique, make it interesting, make it fast
When you're writing from a character's perspective, you often have an idea of what that character is like already floating around in your head. You can implement that personality into your writing easily. Fit in your main character's thoughts here and there, make that character interact with others in a unique and interesting way, and voila! you have a surefire way of snagging readers with your distinct and engrossing character.
2. Hey, I just met you, and this is crazy, but here's my number...(okay I'll just shut up now...)
When a book is written in first-person, I often finding myself wondering, 'Would I react to this scenario like the main character did?' I find myself connecting with the MC's actions and feelings, and thus I find myself more interested in that character, and therefore more interested in the book. The main character quickly becomes my personal BFF in the book-world she is guiding me through.
1. Why are you so stupid, Main Character?
Realize that the whole plot of your book is inside the main character's head. So anything that the main character doesn't experience in some way...well, you just can't include it.
So, what if this detail is important to the overall plot line but you can't include it because the main character wasn't there when it happened? What if all the other characters know something the main character doesn't and the reader HAS to know what the main character doesn't know but the main character is the narrator of the story so how does the reader find out that information?
I'm sorry. Really, I'm very very sorry. I cannot help you.
2. One viewpoint, one story. One direction. (just made a 1D reference right there...anyone? anyone?)
When writing from one viewpoint, you'd better be sure that it is a viewpoint that can take you through the WHOLE ENTIRE story without becoming boring. Which means your character better be interesting...AND consistent. If you have a bland POV, the reader will become aware of the fact that your character is not interesting, and therefore your book is not interesting. And as for consistency...if your character is moody and angry for one chapter and happy and joyful for another chapter for absolutely no reason, your reader gets disoriented and confused, and will thus let go of your book.
See Veronica Roth's comment on first-person writing here.