Dramatically reduce the amt of space used by OSX

Question

I have a late 09' Mac Mini that's recently been upgraded from 2GB to 8GB of DDR3 1066Mhz RAM.
Plus, it's had it's 2.5" 5400RPM 160GB HDD replaced by a 240GB SSD...
With SSD's, it's typically a good idea to have at least 10% of the total capacity allocated as free space (how much depends on the SSD)
I just upgraded from SL (with all the latest updates applied) to Mavericks, & I noticed that the latter is using far more space.*
On SL 7.1GB was used & on Mavericks 11.6GB is now used, & I haven't even applied all the latest updates to Mavericks yet!**
Looking for tips on how to greatly reduce the space used, without greatly reducing the capability/functionality/utility of the OS.
Thank-you.
*both were clean OSX installs, only native/stock apps, no 3rd-party ones yet
**actually, it looks like it's auto-updated to the latest build of OSX, I just used the update tool & the only update left was for iBooks

Answer 1

Tony T1 wrote:
My guess is that the space increased was due to the sleep image increase when you added 6G of RAM.
You can have the mini only use RAM for sleep. 
The downside is that if you loose power while sleeping, then the sleep image will be gone.  Updside is 8G of diskspace reclaimed.
In Terminal, run:
    pmset -g
Look for hibernatemode
     If it's hibernatemode=3, then "The system will store a copy of memory to persistent storage (the disk)"
     If it's hibernatemode=0, then "The system will not back memory up to persistent storage"
If hibernatemode=3, look for the sleepimage with:
     ls -l /var/vm/sleepimage
To reclaim disk space:
In Terminal:
     sudo pmset hibernatemode 0
Then you have to remove the sleepimage with:
     sudo rm -i /var/vm/sleepimage
For more infor, see: man pmset
Okay finally had a chance to check this, nope it's set to: hibernatemode 0
Also did a ls -l /var/vm/sleepimage & got: "No so such file or directory"
I also did a ls -al in /var/vm & saw 2x swapfiles which seem to be taking a considerable amount of space.
These generally shouldn't be touched, right?
After reading that article you linked to & others it linked to, + some other reading before them, I'm 100% sure I don't want hibernatemode 1.
Resume/Autosave/Versions etc, + the FS's natural journaling abiities are more than enough for a desktop like the Mini.
So back to my original question, what else can be done to reduce space used?
I've done lots of research/reading since, but I'm still not 100% happy with the reductions.
I've come a long way though, largely by using symlinks to redirect data heavy dirs in my home dir, haven't touched ~/Library & am reluctant to for various reasons.