Here's my plan for you: go to Goldsmiths and study art for about ten or five years or so, and THEN redo your past work, or get a job as a Professional artist.
On a lighter note, have you seen James Cameron's Avatar yet?, if not, that could motivate you into drawing more.
Some examples of what I mean:
Amplified Mobility Platform (AMP Suit): [link]
AT-99 “Scorpion” Gunship: [link]
C-21 Dragon Assault Ship: [link]
Oh, and I allmost forgot: [link]
(I'm not against you or anything, but I see great potential in you, therefore, it is my responsibility to steer you in the right direction and to make sure that one day you will be a famous artist, I promise you.)