In this mini-article i'll explain how to change color in your profile. You can see here example. I do not speak about background pictures, i'll explain this thing in next message.
So, the first, about you have to know, is that all changes we will write in "About Me" field. You can find them here: "Go to control panel" --> "Settings" --> "Edit personal info" (bookmark). "About Me" is a large text field under "Your status".
We will write CSS code, it's not very hard.
Ok, lets try change something!
Copy this text to "About Me" to change your headers color:

<style>

h1 { color: red; }

</style>

(Things that can be changed are marked by italic)
And all headers in your profile will be red. By the way, you can choose any color as you wish:
red, pink, orange, yellow, darkviolet, lime, green, teal, skyblue, blue, tan...
Full list of colors see here.
To change link color write this:

<style>

a { color: deepskyblue; }

</style>

You can combine link and headers color:

<style>

h1 { color: red; }

a { color: deepskyblue; }

</style>

As you can see, we always use style tag, it is necessary for correct display!
To change all other text copy this text:

<style>

#main_content { color: yellow; }

</style>

Here that it has turned out finally:

This is my multi-coloured profile =)

<style>

h1 { color: red; }

a { color: deepskyblue; }

#main_content { color: yellow; }

</style>

If you have any questions, or any remark, please, contact me!