Help with a styling issue, not sure to use div, id, class, etc.

Hi,

I am trying to style a 3 column page layout to my wordpress pages and post through the use of calling up a class (learning CSS and HTML as I go so please bear with my terminology and redundancy in code.)

The CSS I have so far is this:

p.column1, p.column2, p.column3{
float: left;
width:30%;
}

p.column1 {
background-color: transparent;
background: url('themes/images/bgback1.jpg') no-repeat top;
background-attachment: scroll;
background-x-position: 0%;
background-y-position: 0%;
background-repeat: no-repeat;
width: 115px;
margin-top: auto;
margin-right: 45px;
margin-bottom: auto;
margin-left: auto;
padding-left: 10px;
padding-right: 20px;
padding-top: 0px;
padding-bottom: 10px;
}

p.column2 {
background-color: transparent;
background: url('themes/images/bgback.jpg') no-repeat top;
background-attachment: scroll;
background-x-position: 0%;
background-y-position: 0%;
background-repeat: no-repeat;
width: 115px;
margin-top: auto;
margin-right: 45px;
margin-bottom: auto;
margin-left: auto;
padding-left: 10px;
padding-right: 20px;
padding-top: 0px;
padding-bottom: 10px;
}

p.column3 {
background-color: transparent;
background: url('themes/images/bgback.jpg') no-repeat top;
background-attachment: scroll;
background-x-position: 0%;
background-y-position: 0%;
background-repeat: no-repeat;
width: 115px;
margin-top: auto;
margin-right: 0px;
margin-bottom: auto;
margin-left: auto;
padding-left: 10px;
padding-right: 20px;
padding-top: 0px;
padding-bottom: 10px;
}

The HTML and how it outputs per the attached file is this:

<p class="column1">What To Buy
Pink or Blue Widgets. Pink or blue widgets. Pink or Blue widgets.
Learn More</p>

<p class="column2"> How To Buy
Some tips and deals. Some tips and deals. Some tips and deals.
Learn More</p>

<p class="column3"> How To Use
How to use your pink and blue widgets
Learn More</p>

Questions:

Not sure how to style each of the text independently, example would like the "How To..." to be bold. The middle section to be smaller text and a different color. And the bottom "Learn More" text to be styled another way. As right now it is defaulting to the ".p" css style I believe.

Not sure what sort of selector I should be using for the css. Also not sure how to style a class within a class, if that is even possible.

Hope someone can help me out here. thanks again.