For this P&ID, I start with looking at it and determining a general strategy of how to complete it efficiently. It is not to scale, so objects are sized relative to each other. There are many instrumentation objects that are repeated, so it is best to create reuseable blocks with attributes to easily insert and specify the instrumentation specifications and numbers.
Usually, the flow goes from left to right, so I start at the source at the middle left. There can be a confusing number of routes, but looking at it you can see about 3 main areas, so going left to right I drew each section, adding to appropriate layers as they were checked and completed to avoid confusion.
This is a good example of a drawing that goes very quickly once a general strategy and initial blocks are created. W blocks could also be written and accessed for future drawings.
