What am I doing wrong with my Skyboxes? So many glitches...

You don't need any custom geometry to add a standard Skybox, just do the following:

1. Go to Edit -> Render Settings

2. Click on the "Skyboxes" folder inside the "Standard Assets" folder

3. Drag one of the materials from there into the "Skybox Material" in the inspector

Tada! Skybox!

Hi. I'm something of a noob as well so I'm not going to say that the way you're doing the skybox is "wrong", but I've never seen it done the way you're trying to do it. The skybox shouldn't be an actual object in the scene, so go ahead and delete it. Instead you need to create a Skybox Material (create a new material and then, with the new material selected, choose Skybox shader in the shader drop-down menu in the properties panel). After that you'll see the six texture slots for your skybox textures, so go ahead and drag them into their corresponding slots. Finally, under Edit -> Render settings, you'll see a slot for a skybox material, drag your new material onto this slot and your skybox should be instantly visible in the editor.