Your use of the eraser seems quite random.
Also black and white on vibrant blue background...
The thing with tech brush is that people generally just fill the space with it and seems to think it'll do the job - it doesn't exactly that way.
Like with anything related to visual arts, it's mainly a matter of spatial organization. That mostly comes with experience, I suppose (because I really have no words to describe it, the actual theories on a succesful spatial organization is mathematical and has complicated scientific explanations behind)
One hint I can give you for starter though, is to -not- do large signatures to begin with. This is a general mistake all beginners do, because they like it big, want to add a lot of stuffs. Try smaller format.
Do things cleaner, simplier. The more you try to add components, greater its complexity, harder is the spatial organization, and harder still to blend every components in a whole.
//[/b]@'Mike':[/b] I'm actually trying to join Maersk, I've sent an application and it's been a long time and no one has answer'd yet.//
ANYWAY, @Yue Fei: Hmmm, you're right. I'll start trying to make somethin' simpler, with less "spammage" of the tech brushes and eraser.
This actually helps very much! Thanks!:D