Also - a tablet. It's not necessary, it doesn't do anything more but its just more comfortable then using a mouse. A mouse makes painting faster because of its pen pressure - means you don't need to change the size of the brush so often and a pen itself is more comfortable to hold in hand than mouse.. but other than that - it does nothing more. I have to admit that if you're seriously thinking about digital painting it'd be really hard to do it without a proper tablet, but don't ever believe that the quality of the artwork itself has anything to do with that. Another very helpful thing you should remember are the shortcuts common to most programs (I tested them in Photoshop 7 and Painter 7). While having a brush selected holding it with left ALT will switch it to eyedropper tool, with left CTRL you can move current active layer, with these two [ ] you change the size of your brush and also holding SPACE let's you move the whole picture (very useful when zoomed), CTRL +/- zooms in and out.. using all of these makes your work 100% faster and you can focus on painting only.
Another thing you need to do is to choose a general colour scheme or just some background colour.. Check the image with skintones and background samples pasted previously to see how big difference the background makes. It won't be needed if you're colouring the comic drawing, but when you're painting with many colours it will be more or less transparent and also you have to make sure all of them match together. The sketch can be terribly messy, it won't be used for nothing more than just guidelines later. After placing some basice shades and shapes in colours there comes the hardest part - refining the shades.
Compare these two.
It looks simple, but took quite a lot of time of painting over and over, blending colours of different shades to make it look good. There are no tricks here - you just have to have some patience and blend all of it together, mix colours and shades until you're satisfied
And here's another tip - paint on a big canvas size in big resolution (200-300dpi). Bigger than you plan the pic to be. Why? Because if the resolution is high the picture will have a higher quality and, can be printed later (300dpi is a setting for printing pics in magazines and books, it's the amount of pixels you get per inch.. so 72dpi is enough for your website portfolio, but being such low amount, it would look really bad when printed). Also if the picture is bigger you can approach it in a similar way to a full size traditional drawing - with lots of lines and dots which create better effects than blurring and smudging colours on the small pic. Look at the close-ups.. This is how it looks in 100%, but when you see it in 80% it looks good, yet not blurred
Basically all you do now is painting over and over.. Refining the shades.. Do not use too many shades of colours though.. That's what I do often and the painting looks "too finished", so I often have to paint some colour
on to it, to make it look smoother.
Another important thing is - don't use black. Black is the color which doesn't exist in nature, looks good in the comic drawing, but not in the painting which is a mixture of various shades of one colour.. If some parts are so dark that they look black I'll add it later. In general I'm using very dark shades of colours which look almost black, but still has their own saturation.
The next step is to paint some background, it'd be smarter to paint some of it at the beginning and just refine it later but as this was one of my first paintings I was still thinking too much in lines not shapes about it. I decided she'll be sitting in the swamp, so I just painted lots of brown-green lines, then I refined them with some smaller lines and painted "shadows" of plants. Then I added some colours to the outlines of plants. Remember that the brush you're using must be partly transparent so the colours can mix together like with traditional brushes.
Then I'm painting the rest of the background - look at the reference pics I've pasted at the top of this tutorial. They're different, but you can see how I've been using them to see how looks the line of the coast etc. I try not to use too many layers, because with too many you can easily loose the trace of the picture.. When I paint something detailed I use up to 3 - 4 layers to get it right and experiment but after that I merge them, so all the time I have max. 5 - 6 layers..