You probably know the concept 'semantic web' and are familiar with some specific aspects (parts? features?) of emerging semantic web technologies.
To fill in the gap between concept and individual parts though -- to walk you from high-level ideas to gritty details -- this new blog series from Adrian Gschwend will serve you well.
The first post runs quickly through the basics; then, in the third paragraph, heads straight for practical application.
Your first assignment? Create a friend-of-a-friend (FOAF) representation of yourself. Adrian provides some great examples:
I recommend to create a FOAF representation of yourself. Check some examples to get some hints: me (Adrian), Bart and Christian. Tim Berners-Lee has a more advanced but also more complex one. You might want to create this with some help first and then adjust it according to the FOAF specification.
The rest of the post includes lots of tools for making RDF work easier (most awesomely Graphviz), so take a look and start your journey to semantic web gurudom.