Lock and Key by Sarah Dessen

I've read a lot of Dessen's books, but out of all her many books, this I have to say, is the best one.
Lock and Key is about a teenage girl named Ruby who lived in an old yellow house because her mother mysteriously disappeared from Ruby, so poor girl she has no choice but to live alone. Unfortunately for Ruby a social worker visits the old yellow house and asks Ruby why she was living alone.
Ruby knows the jig is up and goes to live with her newly married elder sister Cora and her rich entrepreneur husband Jamie. Although Ruby now lives in a luxurious house, gets whatever she wants, and goes to a rich kid's private school, she still can't seem to be grateful for everyone and everything around her. Cora thinks Ruby is having some problems fitting into her new school, but unfortunately it's not that simple.
To find out what's the real reason Ruby can't find her happiness, it might be good to read this book.
Also, don't try and do it the easy way and search on Google what happens next. Nothing can beat the joy of actually reading this book.

The No.1 Detective Ladies Agency by Alexander McCall Smith

If you're into crime and mystery, this is definitely the book for you.
This book is about a character called Mma Ramotswe. Her real name is Precious, but out of respect people call her Mma Ramotswe. She is a detective in Botswana, and a clever one at that. The first book in this series is a collection of her encounters with notorious criminals and her odd clients. Most of her mysteries seem complicated but in the end turn out to be very simple and ridiculous. The No.1 Ladies Detective Agency includes quite a bit of comedy as well; Mma Ramotswe is a very comical character. If you're wondering about the strange names, the story is set in Botswana so it was completely normal then to have names like, "Pretty" and "Big".
Thank You for reading this! Actually, you should be the one thanking me because I am doing you a favor actually recommending this book to you. :D

Sweethearts by Sara Zarr

Although a bit sad, this book is amazing for mystery/romance lovers.Many years ago, when Jennifer Harris was still in Kindergarten, she met a boy in her class named Cameron Quick.
Not before long, they realize that they are both social outcasts and soon become the best of friends. Cameron is a very nice boy, but he also is strange. For example, one day when Jennifer and Cameron were in 4th grade, Cameron gave Jennifer a genuine amethyst ring! Cameron claimed he found the ring in their school parking lot. However, during Jennifer's year in 5th grade, she finds Cameron missing from school and soon learns from her teacher that he has unexpectedly died!
    Now, when Jennifer (now known as Jenna Haughen) is in High School, she has forgotten about Cameron and his mysterious death, and instead is happy and popular. However on her seventeenth birthday, Jennifer spots a note on her desk from no other than Cameron Quick! It says happy birthday. Then, Jennifer sees Cameron at school and gets even MORE alarmed. Did Cameron Quick wake up from the dead?
 If you want to know the answer, I highly suggest reading the book. It's not that long , so if you don't like long books than you don't have a problem. Happy reading! :)