PDF File size Export issues

Hi all.

I have been struggling the last few times to export my pdf's from Illustrator to an email size.

I need my files to be below 10 MB and it's just not exporting to that size.

I have ensured the following is done:

1.  Outlines of text is created

2. Rasterized my images. I even rasterized the whole document down to 72 ppi. 

3. Ensure all my images are linked and not embedded.

4. The document is compressed to 72 ppi when saved to PDF. 

5. I even changed my document preferences to 72 ppi. 

One day it is easy, the next day it's a struggle.

What am I doing wrong?