Jurgen - one word... PRACTICE!!
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Practice different spraying techniques (detail, large coverage etc..) practice using different thinning ratios until you find what works for you. Practice some more! Use an empty milk jug or other plastic container with different compund curves on it, or if you have old models you can paint on those too. It shouldn't take you too long (a matter of an hour or two) until you should be reasonably ok at putting an even coat down for large coverage, the detail comes with more experience. I even use a sheet of paper and try to get the smallest pattern I can then varying the width of the line as I move the airbrush across the page.
That airbrush looks like it will work well for you. If you spray acrylics using a needle lubricant is a must, it helps keep the paint from drying on the needle and blocking the spray pattern. It helps with enamels too. It is only about $5 US a bottle.
The biggest thing is don't get discouraged if you make a mistake or it doesn't look as well as you wanted it to the first few times you use it. It all comes down to experience and practice.
Good luck to you!