It is bad form to give each individual element within a drawing its own properties rather than assigning it a layer so that everything with the same properties can be assigned like attributes without needing to search through every single line of the drawing.
Likewise, naming the layers in a useful manner is generally encouraged – trust me – it makes for happier consultants. Something that looks like a car registration is not useful, something simple such as “Brick” is. Hell, throw in the NBS classification if you want to look flash, at least we’ll understand it!
Everything that is a brick should be on the same layer as everything else that’s a brick, that way if you want to know where all the bricks are you can isolate the layer named “Brick”. this will cut down on search time.
Polylines and Blocks have there place – they are not the solution to everything. And no, neither are X-Refs. And don’t forget to regularly purge drawings for all of those tricky little elements that have crept in unannounced.
If you can draw it with one line, draw it with one line – not five. I don’t care if you had to zoom out to do so, you should be inputting by dimensions anyway to ensure accuracy.
Architectural schools really need to start teaching the fundamentals of good drawing practice, that way random people won’t have to rant about it on the web…