I use Tamiya thinners only with their paint. It sounds like you are too far away. I spray from about 2 inches or so with low pressure (about 12ish PSI or a little closer to 20 if I'm using my siphon feed brush. I'm still learning too but I'm finding after a light coat I spray it untill it looks wet. Almsot to the point of running.
I've had problems too were my paint is almost pouris [sp] and seems like it will actually absorb my future coat. Sometimes I'll rub my model down with 2000 grit sand paper or even a coffee filter to knock that first layer off and get a smooth surface.
I've been airbrushing for about a year and a bit (through 5 models) and I'm just know starting to really figure it out. You can read tips and tricks all day but what counts is practice. :)
Oh and as for cleaning your brush I suggest Windex. It dissolves Tamiya acrylics like crazy and it's dirt cheap.