How much space should be used on HD for Linux?
 

I will be adding a partition on a one tetra HD as a dual boot on a Win 7 machine.
How much space should I use for a Linux partition?
Any helpful hints for a Linux newbie?

Most distros will be installable on a 5GB partition or less but you will need more if you start installing software. If disk space is an issue 15 GB should be ok. Otherwise make it 50GB to be on the safe side. (I don't think I ever used more then 25 for the root filesystem on my computer.)
This is assuming that you are putting userdata on a separate partition.
Also note that you'll need a swap partition.

I have 8gig of RAM and there will be only me as a user. Does this make a difference?

Not really. The RAM size affects the swap partition size. If you want to use "suspend" you need a swap partition at least as large as your RAM.
You being the only user makes no difference at all. You will still want your data on a separate partition. This is also the best way to be able to access it from both Linux and Windows. (Windows does not read the ext filesystem, which is the typical filesystem to install linux on.)
How is your Windows set up? Do you have a data partition? In that case it would be easy to mount that from within Linux.
Otherwise it gets a bit more complicated, but you can still mount your user directory. Read up on /etc/fstab and bind mounts.

For every time I learn something, I also have more questions appear. :) I am still at the stage where I do not even know what I do not know.
I will read up an the things you mentioned.
I have an old 120gb external HD I have set aside for both Windows and Linux moves etc.
I am thinking that I better make my new Linux partition 100 gig. That way I should have room to divide it more in the future. Have you a link that you have found very helpful for learning this stuff? I have four PDF's downloaded including Linux for Dummies #9. The others are simpler. I somewhat remember a share file or something like that for both Win and Linux. My original idea was 250 GB partition for Linux stuff.

100 gig will be way enough. 250 gigs would be a waste of space. You'll never use them. I personally learned the trial-and-error way. Plus using search engines and this forum... Working through the Linux from scratch book tought me some stuff, too, but it's probably a bit of an overkill for most users.
http://www.linuxfromscratch.org/lfs/

Most of the major Linux distributions will take about 5-6GB or less for a minimal install. You should also be able to get this information from the site you download from. Given the size of drives today, for a root filesystem, 15-20GB is generally more than enough and you can then create a separate data partition for whatever you have; pictures, movies, music or whatever. You could also create a data partition to access from windows and Linux.

Thanks Joe... New shortcut for my desktop(Temporary) and my USB2 External HD. This should be enough to keep me busy for a while. And 100 GB is what I will set aside for Linux Mint.

You are welcome :)