STEP 1 SKETCH: So first things first, I always start with a sketch. Now, I'm no expert by any means. I'm still learning, but then again, we should never stop learning, but I think the sketch is the most important stage. Just draw and have fun fleshing out the idea.
STEP 2 VECTORIZE: Once you're happy with your layout, you can scan in your beautiful sketch and start building the illustration out in Adobe Illustrator. Every body part and clothing article has to be a separate vector. Check out the Rhino's head as an example below. Some people prefer to build out everything directly in Photoshop, but right now I feel more control in Illustrator. Once that's done you can move over to Photoshop for the real work.
STEP 3 TEXTURE: This is the moment you're going to paint in the texture that makes the illustration what it is. First, your vector shapes can now be pasted onto your Photoshop artboard (keep a copy of your sketch on the bottom layer and you'll notice your layers lock into place pretty decently with little fuss). You will have multiple layers, so for example, I kept all the Spidey shapes in one group and all the Lizard shapes in another group and so on. Make sure not to have any shapes overlapping on the same layer either. This might seem like a lot of work, but hey you asked. Since each shape is on its own layer, I can lock the transparent pixels (in the Photoshop layers palette, click on the little checker board beside the word Lock). Now you can paint only where there are already objects. I can now use my brushes on the individual shapes and not have to worry about keeping inside the lines. It's the best!
STEP 5 TOUCH UP: Now you have your illustration pretty much done, but you might notice some of your color choices seem off. No problem! Since all your layers are separate you can tweak the colors using SELECTIVE COLOR found under OBJECT then ADJUSTMENTS. Or you can use HUE/SATURATION also found under ADJUSTMENTS. Whatever works for you. Below is the before and after. The changes may be subtle to you, but it made a big difference to me.
Conclusion: So that's my process. I hope this helps you out, but if I skipped over anything that's still got you scratching your noodle, ask away in the comments section. And if you'd like to buy this limited edition print, click right here. I hope you enjoyed my first official tutorial!
Dennis (aka tanoshiboy)