I'm using wordpress for my blog/site. I'm using Freshnews theme from woothemes because the theme for that blog.

This is actually the link: http://demo.woothemes.com/freshnews/

The font isn't that good which is far too small , the spacing isn't good (too stuffed up).

How do you alter the fonts, size, spacing (line and paragraph) through the blog.

I understand I would need to change it out somewhere within the stylesheet. But where exactly and just how?

And do you know the ways to accomplish this?

Must I use a font somewhere?

Must I use webfonts (like google webfonts)? What's the advantage in making use of this?

or do you know the different ways?

Freshnews is just one of woothemes older templates but should include a custom.css file inside your root folder. This file can be used to override styles inside your styles style sheet. You will need to use chrome developer tools or firebug to find out which fonts you need to adjust.

I suppose you wan to modify your p tags, to regulate the font family, size, and line-height to so in custom.css place the following. Observe that you will find many styles to edit to obtain all of the font dimensions modified. Your best choice is by using chrome developer tool or firebug to obtain the class and ID's from the styles you need to edit.

.entry p {
font-size: 1.2em;
}
p {
font-size: 1.2em;
}