The morph target technique I covered in the video is a very common way to control the placement of your details. It can also be used as an 'eraser' tool when you store your morph target in the clean base mesh:
Another really cool thing you can do with the AdjustLast slider I mentioned in the video is to use the Undo History. In other words, you are not limited to only 'adjusting' the last stroke; you can actually hold Ctrl and click on the timeline. Once a point is saved (grey rectangle in the undo history), any stroke you make after that point will be included when you use the AdjustLast feature:
Finally, here is another cool tip to use the detailing brushes to sculpt more 'random secondary shapes': Draw a stroke and then go to the Masking Palette and click on 'Mask Changed Points.' This will mask everything that was changed from the last stroke you made. Then you can invert the masking:
Once you invert the mask, you can use the Inflate and the Polish sliders from the Deformation palette to add more volume and smooth out the unmasked areas:
That basically will create additional secondary clean shapes, and then you can go over again with another detailing brush to add the surface details: