Whoa, don't ever use a tutorial asset in your portfolio, especially one that takes you step by step through the process. I have talked to developers that said they will immediately dismiss a portfolio if they recognize an asset from a tutorial. They want to see what you can come up with, not go step by step as someone else…
Yikes man... I won't talk about the tutorial deal, but I think that first and foremost you really just need to go back to basics. Take a single prop and really go back to taking things step by step. Starting with modeling efficiently, then defining your materials and matching examples from life. Don't get discouraged here…