Creating materials that look like real objects

How do i turn an object into something useable?

i.e. - an alien or a spaceship that actually looks nice

Edit:

Take Lurpz (or whatever the tutorials characters name is),how do i get something to look like that?

If I am understanding your question, then you need to use a 3D modeling software such as 3D Studio Max (pricey) or Blender (free).

Start with a simple model, UV map it, and use a material that is Bumped. Using a paint program, draw both a coloring texture and a bump texture (dark is low, White is high), being sure to set the texture type to Normal Map in the import settings.

Have a look at the Lerpz character’s mesh and materials to get an idea.

This isn’t easy. You need to develop artistic skills. But provided you start with simple characters (more cartoony than real world), you can start developing those skills.

Also note that the modelling program you use may have different features to help you, like texture painting or normal map baking or Z brushing. Learn about it’s features.