When ballasting turnouts, it's helpful to paint the roadbed, especially in the area of the points, a colour similar to that of your ballast. That way, you can keep the ballast application fairly thin between the ties over which the points move, and the barer spots will not be noticeable. You
may fill the ballast level with the tops of the ties, if you wish, but definitely no higher. I prefer about half the height of the tie or so. For the rest of the turnout, apply ballast as you would on any track. Use a small screwdriver or knife blade to clean any stray ballast out of flangeways. Now, lightly grasping the ferrule of the 1/2" brush that you used to spread the ballast, lay the handle across the rails and lightly and rapidly tap it as you move along the rails. This will cause any ballast lying on the tops of ties or rail flanges to bounce into place between the ties. Using some plastic compatible oil, spread it on the tops of all ties over which the point rails move: you don't have to cover the entire tie top, just the section over which the points travel. Flip the points back and forth several times to ensure that everything is properly coated, then park the points in mid-throw, so that they touch neither stock rail. Now spray the entire area with "wet" water, then apply your 50/50 mixture of white glue. I use a dropper-style of bottle, which allows precise placement of the glue, but with a greater capacity than an eye-dropper. Try to be neat around the points, but don't skimp on the glue any more that you would elsewhere. Now, get lost for a day or two until the glue dries.
If you're very lucky, your switchpoints will move as if nothing has changed. More likely, they won't move - don't force them. Usually, a little back-and-forth finger pressure, applied to each point rail separately, will free things up. Apply the pressure over the entire length of the moveable rail, too. When things begin to move, you may have to repeat this operation as the points move towards each of the stock rails, as there may be some glue build-up on the tie tops, despite the application of oil.
That's about all there is to it. Many switches (turnouts) have darker ballast around them, as the moveable parts (the points and the ties under them, too) are greased liberally. I used cinder ballast around most of the points in this photo, but I'll eventually go back and apply some additional weathering, too.
Wayne