Hi shrepX,
I am a concept artist in the game industry and concept art like you see on the mags is what I do everyday. The standard workflow is :
1. First of all and the most important one is that some artist will start by looking for reference images online about the subject that they are about to base their drawings on.
2. They will make rough thumbnail sketches like IslanderNL mentioned in order to get a rough idea about the composition, because it is easier to analyse the drawing on a small scale than a large one and balance it accordingly. (some do the sketches directly on the monitor by using a graphic tablet while others like me, prefer to start on paper...I just love the feel of paper)
3. Then, after we have decided about the composition we start to draw seriously now. We know what we want as we had references and thumbnails to help us nail the idea. (knowing what you want is very important)
4. Scanning of the drawing at 300 DPI most of the time and we send it to a digital painting program like photoshop or painter and we start doing the digital painting (using a graphic tablet like Wacom Intous 3). Some artists still do the painting traditionally and then do some minor retouches on photoshop.
5. Sometimes you have to take a break like one day from the painting in order to start with a fresh look at it again. If you are looking at a drawing too much, you get saturated with it and might not notice if there is anything that is not working with the concept.
6. You enjoy that feeling of creation.
For character drawing, knowing anatomy is very important.
For environment you need to learn perspective and do a lot of outdoor practice.
For others like vehicle designs and creatures there is nothing better that good reference images to inspire you.
Taking pictures of everything that catches your attention wherever you go helps to develop your sense of attention to detail and further develop how you annalyse everything that's around you.
This is a drawing i did using the same technique metioned above.
hope you like it. It was done in 4 days (working at least 3hours per day)