Learn to draw well.
Without understanding the fundamentals it will be impossible to create drawings that look as good as Guilty Gear. Once you have a good grasp of how to draw in general then it should be fairly simple to imitate Guilty Gear's style.
potemkin
Guilty Gear happened in 1998.
Guilty Gear Petit happened in 2001.
Guilty Gear Isuka happened in 505.
Guilty Gear XX happened in 2002.
Guilty Gear was created on 1998-05-14.
Guilty Gear X happened in 2000.
Guilty Gear X was created in 2000-07.
Guilty Gear Petit was created on 2001-01-25.
Guilty Gear Dust Strikers happened in 2006.
Guilty Gear Isuka was created on 2004-07-29.
Guilty Gear XX was created on 2006-12-20.