walto,
Don’t think of it as “sketching a perspective view.” Think of it as building the Queen Anne platform, piece by piece, and then putting the pieces together.
The activity you’re performing is “modeling.” Although you use tools to draw shapes as you work, the analogy is really much closer to building than drawing. As for the view, that will take care of itself: you concentrate on the workpiece and let SU’s orbit, pan, and zoom controls give you exactly the view you need to see what you’re doing at any given time. You shouldn’t even have to think about adjusting your view as you work, any more than you have to think about bending over something in the real world to get a better look at it.
So start building individual pieces first, gradually adding detail. Then group or make components of those pieces, then snap them together with gratifying precision.
-Gully