Edit: I should add! Keeping a reference photo of a real cat nearby is always good. Even if it's not the specific breed of cat you're drawing, you can learn a lot about it's colouring and how it reacts with light from a real photo.
Edit2!: I don't recommend using straight black for lineart. I suggest a darker version of your base colour. Black can look too harsh sometimes
I've had a couple of people ask me about how I colour cats, or just expressing that they like it. *Aishun suggested I make a tutorial so I did! I've never made one before so I'm sorry if it's confusing. It's very big so you'll have to download it to be able to see everything.
This cat was for a friend of mine (and will be posted with a batch of other requests soon), so there are watermarks all over the images. I don't think it disrupts the images themselves since I made them very light, but I don't want them stolen.
Like it says, feel free to ask questions! I'm not sure I explained things very well there (I know the time on the screen shots goes for a few hours, but it really doesn't take that long I promise! Was just saving my steps, eating, etc)
Click the box that's beside the red X at the top of the image window and you'll be able to play with the size. When you open new windows you can place them next to your main drawing