WHY WON'T ITUNES BACK UP MY IPHONE WHEN I JUST MADE SPACE ON MY MACBOOK AIR?

I just spent all morning deleting all my photos on file in my laptop (saved them in an album on photobucket) and all the apps I don't need and I'm trying to back up my iphone5 to itunes and it still is saying that my phone can't be backed up because there's not enough free space on my macbook air which is honestly impossible because I deleted So much. I barely have anything on here now.

What do I do now, because I don't want to have to go into apple because that's such a hassle.

I understand your concern, I will be happy to help you with this.

First, you should move the mouse to the top left side of the screen, click the Apple and click "About this Mac". Click "More Information" and then click the storage option. This will give you an idea of how much space is on the Macbook Air

You can plug in the iPhone to the Mac, and manually go through and deselect items which you do not want synced, also, it might be a good idea to delete pointless trash from the iPhone including App's and photos.