My first completed Digital Painting. It took a lot of work, especially since I'm a noob. But really, the main things needed here are keen observation, time and persistence.
Now, since at this point I do have more control with pencil and paper, I made a quick sketch and scanned it; Opened it on Photoshop and proceeded to sketch and shade over it with my Graphics Tablet. It's a quick trick you can use if you feel more comfortable with pencil.
I won't lie, this doesn't make the process any less time-consuming or somehow magically easy, but having an outline ready makes it seem much less daunting than having a blank white page on Photoshop, especially when you're starting out with Digital Painting.
With this finally completed, I will definitely try and venture into using colour. It might seem scary when you're starting out, but a few sketches by hand go a long way, even just to have a few ideas in front of you.
An important thing to keep in mind is not to worry about getting it perfect the first time you're drawing a line or filling in a strand of hair. You'll get to go back, add detail and perfection everything as you go along, bit by bit.
The most important thing however, is to work in layers. Like - for example - sectioning off different layers to the face: base colour, shading, highlight, freckles, etc. It will help immensely.