First, for hand painting I use hubmrol enemal paint (other model enemal brands are also fine) thinned with minerial sprits untill it is roughly twice as thick as milk.
Acrylic paint is horrible for hand painting where a actualy brush stroke is involved.
With enemal paint thinned this much it will give you a good work time. One example is the bottom hull of tanks, i sometimes stroke as far over as an inch over wet paint to smooth out ridges of paint left on the edge of the brush stroke.
The direction i paint is the direction that will give me the longest strokes, but this is not a must.
Here is a example of good and bad brush stroke directions.
<<<< >>>> = good / <<<< <<<< = good / <<<< ^^^^ = bad.
The whole goal of all this is to make the paint perfectly smooth and flat. When done right, a layer of dull coat will even out the paint texture to give you a very near AB finish. Raised ridges of paint will be highly visable.
I assemble the model as much as i can
BUT i leave off all small parts that stick out on a otherwise large surface area, such as a handle. This is because these parts will collect a lot of excess paint and leave a "wake" like form a ship of lack of paint.
If you know this then pay no attention. You will want to apply several thin layers of paint rather then one thick one that will fill in details. I apply 2 to 4 layers. The first one will look terrible but this is normal, each layer will be a more solid color untill it is done.
Mongol General: Conan, What is best in life?
Conan: To crush your enemies, see them driven befor you, and hear the lamentations of the woman!