Empathy

What makes you cry?
I can give you a list of things that bring tears to my eyes: certain books (Fearless, The Fault in Our Stars), seeing people being kind without getting anything in return, people who are impoverished but still give to others, and being able to serve others.  Maybe for you it's seeing hurting animals or hungry babies.  Perhaps it's when your boyfriend cheats on you or you feel like a failure at school.  Whatever it is, you can channel that into your writing.
It's the same for joy and anger and despair.  People can relate to each other a lot more easily than they think.  If you pour your struggles and victories into your work, the audience will feel the truth behind your words.  We've all experienced something similar.
I believe empathy is the most important thing in writing.  If readers don't empathize, they won't care.  If they don't care, they won't read.  It doesn't matter how awesome or heroic the characters are - if the readers don't empathize, they won't read your books.
On a similar note, something I have to remind myself of constantly is reader targeting.  Many of my friends and family are interested in reading my work and I want all of them to enjoy it.  Is it impossible for a wide audience to be touched by just one person's story?  Of course not.  But it is ambitious to expect your work to touch and affect everyone in the same way.  I want boys and girls, teens and adults, to enjoy my writing alike and that just isn't always possible. 
Does that make sense?  I'll try to say it a little more succinctly:
If I focus on making a specific character easy for everyone to relate to, no one will relate to them.
Not everyone is the same.  Focus on making your character human and don't worry about everyone drawing something from your story.  Not everyone will.  But I can guarantee you this: the people who need to be touched by your story, will be.
May your pens stay sharp!
*Evyn