You'll generally only need one coat of render, and it should be 4-6ml thick. Your aim is to apply the render as flat and smooth as possible. For rendering course bricks, you may need to add a little water to the surface before you start. There are a couple of different techniques to applying render; tilt the hawk onto the trowel and then apply the render at a 45° angle, or you can place the hawk's edge on the wall and brush up from there. If you've got vents on your wall, render up to the vent with a slight overlay around the edges, then cut away when dry to finish.