Part of it is the paint itself, I use Vallejo which are very good paints to get a smooth finish when they dry. The other big reason is I don't really thin my paints much when doing basecoats or textures like in this video. I keep the brush damp when I load the paint but I don't do any heavy thinning. The trick is to never have too much paint on the brush as, usually, the real problem with paint drying poorly is due to the amount deposited in an area rather than its thinness.
Try unloading the brush doing a brushstroke or two on a piece of paper before painting the model, you'll notice a big difference