Google pageSpeed tests

Hi,

I have ran a google pageSpeed test and I only achieve a score of 60%

the things it tells me to fix are:

1. The following publicly cacheable, compressible resources should have a "Vary: Accept-Encoding" header:
   *I dont know what this is, but it is for all CSS files

2. Compressing the following resources with gzip could reduce their transfer size by 35.5KiB (77% reduction).
   But I have GZIP turned on, I have tried having both GZIP on via both the ZC admin or via Cpanel. Why does google think I have not compressed the site?

3)Minifying the following CSS resources could reduce their size by 6KiB (26% reduction).
All CSS files. If I am right in my thinking, this means removing all spaces from the css file and cobining them all into one file??? yes/no??

4. Minifying the following HTML resources could reduce their size by 2.2KiB (10% reduction)
   whole site, no idea what that means tho???

5. The following cacheable resources have a short freshness lifetime. Specify an expiration at least one week in the future for the following resources:
   *All my images, I have no idea what it means, but it is flagged by Google as HIGH PRIORITY

6. The following publicly cacheable, compressible resources should have a "Vary: Accept-Encoding" header:
   again, i have no idea what this is???

So how do I go about fixing all these? as I dont understand Google's generic explanation geared towards dev's

TIA

I have just noticed points 1 and 6 appear to be the same, but point 1 is for the CSS files and point 6 is for the whole site
Cheers

Did you ever get any answers to these questions? I'm working through the same issues on my site.