Looking at the influences, the most prominent being the Japanese guy, it's best to go backwards and find their influences.

The Japanese artist definitely was influenced by MOEBIUS and MILO MANARA. You probably want to check them out. I would assume KATSUHIRO OTOMO from the backgrounds and cyberpunk. There are others in him but I have no idea who.

Not sure who influenced ODA, but it seems like he brought a lot of himself into a Dragonball type format. I think he boosts upward from Dragonball in all ways--design, layout, action, writing, etc.

Myself, I come from JACK KIRBY, JACK DAVIS, WALLY WOOD, JOHN BYRNE, and a little Mazucchelli, Oda, and other. My impact storytelling comes from Kirby and Byrne.

As you try to build your art skills, look at it as a series of categories you need to add to or fill. I call it visual language, and there is the pure draftsmanship side and the storytelling side. If you draw excellent, people will love to look at your stuff, however, it is hollow and won't gain you more than a bit of work and a limited audience. If you can tell stories very well and can write stories people want to read, you don't have to draw as well though that's no excuse to sit down on the job. So you really want to approach both sides as well as possible.

Storytelling, aside from script and writing, is the ability to place images in order to enthuse the reader and improve the story. Most guys these days tend to draw comics that bog the reader or even halt the reader completely and will make a comic something of a hassle to get through. Great older comic artists would use strong variation from panel to panel and elements of art that aren't merely horizontal or vertical (boring). (Note on Zim how I directed the artists to try to never have merely vertical or horizontal elements within scenes--even the characters)

90% of storytelling is in the face. So faces are important, not only the draftsmanship but the ability to emote. I always noticed how many comic guys draw fairly staid faces. Fun and sympathy is in broader expressions that make sense. You don't want the viewer lost in a character's indifference or "cool" or inability to act. Viewers go to faces first. Next come hands. After that it is mostly body posing and then lastly backgrounds.

Backgrounds and grounding are very necessary, though, so learn perspective thoroughly and always draw backgrounds until you can do them effortlessly. It isn't really that hard to do. My backgrounds and that Japanese artist's backgrounds are really simple--REALLY SIMPLE. Don't get fooled by lots of detail: that's just cruise control fooling around. We map out grids for perspectives in 10 seconds and then spend an hour or whatever filling in the grid with little tubes and steps and other small details. Complex backgrounds come when you have a variety of planes and shapes intertwining.

When trying to learn draftsmanship, just take a few hours and copy stuff. If you need to learn more about hands, draw other artists' hands for a while. Or eyes, or faces, or whatever. You will remember their style like words in a visual language you are compiling within yourself.

Ok, good.

Look over the rapidographs. I use them myself for this and that. They are very lazy for many people who want to avoid learning to ink. However, they make great borders, balloons, mechanical stuff, buildings, etc. You can then go over the dead lines with a bit of spoon nib to give depth and flair.

Just look into them. You won't need more than a few. Doing what I do, I use a .35, .5, .6, .8, 1.0, and 1.4. The ,6 is probably useless in that line up. The 1.0 is rarely used. 1.4 is great for borders and balloons and filling in black.

I use the .35 and .5 a lot.