How I went about starting blender:

To start with my blender experience I made some test objects, increasing the difficulty as I progressed.
I started with a rupee (currency from the Zelda series)

Then I started working with multiple objects and made a Guisarme (Medeival weapon; Spear-hook)

After that I moved onto a more intricate object, a wineglass.

Once i had completed the wineglass (which I was quite proud of) i felt comfortable enough to start my real project, a companion cube from the game Portal.

The originals

How I went about making the companion cube:

I started with a cube as the base (it's not called a companion CUBE for nothing). Then i started working on the circles that appear on each face of the cube. At first I used long cylinders that extended from one side the the opposing side but I disliked the tubing that criss-crossed the inner working of the cube. So I reworked the cylinders so that each side had it's own.
Next I started on the light grey shapes extending from the corners. To create these I took a base sqaure and modified it to the appropriate shape (making things rounded and perfectly flat are not easy). After it had been molded to the required shape, I duplicated it and rotated the results accordingly.

Third, I created the light grey portrusions that appear in between the corners (centered on each edge). Using a similar method as the corners, I took a base cube, molded it and duplicated it. The result was satisfactory but not finished.

Lastly, to finish the project off, I created a texture for the companion cube. I was a little hesitant at first because I heard it was challenging. However, it turned out to be surprisingly easy, if a little tedious. Since most of my pieces were duplicates of others, I took the UV layouts and overlapped the important ones. The important ones were the six faces of the cube, and the six faces of the cylinders that appeared on the outside. I overlayed all the circles and sqaures, each with their own kind. Resulting in me only having to create the heart image once, and the pinkish plus that appeared on the dark grey background of the sqaures. Everything else, was left alone and colored light grey.

My result

    Wire frame        Solid,no texture  Solid,textured 

My difficulties:

There was a fairly steep learning curve, but once you start going, you'll advance very quickly. Creating rounded edges for the light grey portrusions was quite difficult, though eventually successful, mostly.