How annoying is it when you need to take a pic like RIGHT NOW but your iPhone pops up some dumb factory message that you need to create more space for storage or purchase more storage???  Seriously.  Does it have to happen in this moment?  

I did a lot of research trying to find an easy answer for this message and there isn't one.  Many sites will tell you that the storage is being taken up by your photos.  But it takes  A LOT of photos and videos to consume 16 GB of space.  The truth is the storage is begin eaten alive by every.single.message (sms) you have ever sent.  This includes video, text and pix messages.  (This is not your email account, that is different)  I know, I know, you went in and slid your finger across the message, clicked delete and assumed it is gone into outer space somewhere but the truth is that little booger and thousands of others are still stored somewhere in the intricate brain of your phone and thereby taking up all of your space.  Here is what I have done (two times in two years) to fix the issue and it works like a charm:

Look at your usage under general settings. It will tell you how much space is taken up on your phone by each app, etc. In my case I had ONE picture on my phone (seriously, ONE), zero music and text messages only from Dec 2013-Jan 2014 (two months) which we all know is nothing. BUT my usage consistently said that my messages were taking up 8.9GB which is a ton of space. 
I researched and the way the iPhone works it never truly deleted your SMS messages when you chose delete. It still stores them. Forever. Until you restore the factory settings to your phone. 

SO... Here is what I did:
1. Went into iTunes on my Mac and Backed up my phone to my Mac, BC my cloud is full too. 

*make sure you remember your passwords for all your apps like Pinterest, FB, Twitter, etc or else you will be requesting them soon. 

2. Then clicked "restore" in Itunes to restore factory settings.

The phone did it all and then I chose to set up my phone as a new iPhone INSTEAD of loading my backup to it BC that only put 8.9GB of invisible messages back onto my phone. 

3.  Once my phone was reconfigured I went into iTunes and synced my backed up contacts and my backed up apps to my phone. Voila. 

I do not ever keep a lot of pics or videos on my phone. I regularly move them into an online service or onto my Mac to keep space free. But now I have 11GB of free space and that is a lot of selfies my friends. 

Remember to BACK IT UP!!!  "You's a big fine woman when you back that thang up"  (gotta drop some hip-hop whenever possible)