My main working tool, I’ve been using Scrivener for years to write film and TV scripts, business papers, articles and now comic book scripts. The way it lets you organize your writing, makes it an order of magnitude better than a regular word processor or script writing software, all for a very low price.
In spite of many other options on the market, Adobe’s tools: Photoshop, Illustrator and InDesign, continue being among the most used by comic book creators. Many people dislike the current creative cloud monthly paying scheme which has resulted in migration to other software alternatives.
Digital printing has to be one of the most revolutionary technologies to hit the comic book self-publish scene in the last few years. Not only does it open the doors for the print on demand (POD) model, but it also allows much better management of reward fulfillment on crowdfunding campaigns and best of all, in my opinion, it lets you print a single copy of your comic, to double-check your art, letters and color in a WYSIWYG form factor. Among different options, KA-BLAM has established a good reputation on this field, their quality is outstanding. You send them your art files as per their simple technical instructions and for less than 10 dollars, including shipping, they will print and send you a copy of your comic book. This is extremely useful, we have printed several “issues” of art and character proposals and always find that when you look at them in printed comic book form, you find things, good and bad, that you never saw on the screen. Highly recommended.