I spent a good few hours with yachting and powerboat instructors this weekend. One of the things they try to emphasise to their students is that waypoints on a route should be carefully placed to make that route easy to execute.
It's a good idea to link a waypoint to something that the person at the helm can see. This defensive approach to passage planning builds in an easy way to keep a check on the GPS feed and to make route that can be sailed even if the GPS stops for some reason. Looking out of the window rather than at a screen is safer and more pleasant as well.
If you can ever place a waypoint so that something conspicuous is abeam you can keep things simple in planning and execution - no need to draw pencil lines on the chart and no need to take bearings with a handheld compass whilst sailing. To make this simple, Nuno draws grey lines to either side and forward in a continuation of the route leg whilst you are making a route or adjusting the position of a waypoint on a route.