To establish your style, survey international comic book art and forge your own perspective on that style. Some artists, like Joe Madureira, took inspiration from manga comics and brought those Asian-based techniques to the superhero monthlies "Deadpool" and "Uncanny X-Men." Remember that style is often content-appropriate and choosing one style or another might limit the material you will work on. For instance, Alan Moore, an author who blends realism with superhero and fantasy elements, has typically favored collaborations with artists like Dave Gibbons and Eddie Campbell, who have detailed and photo-realistic styles.
Each comic book artist must find a balance between the extremes of idealized and realistic details. If you look over a four-year run of "Spiderman," for instance, you will find different comic book artists portraying the comic book character in a range of types, from incredibly beefy superhero to a more realistic young man with thin musculature. On the one hand, the idealized muscle-bound Spiderman gives the character a sense of power and strength. Alternatively, a more realistic Spiderman might give weight to threats from bigger, more intimidating villains and give his battles a "David vs. Goliath" feel.
Consider stripping away the clichés in your art that might alienate some readers. One way comic book artists turn off readers is by drawing anatomically impossible women, with enormous busts and thin waists. Though you can lean toward idealized anatomy, you could baffle female readers. Other common clichés of comic book art are over-drawn male bodies, a lack of background detail, and a limited emotional spectrum for faces and body posture.