Just about the best equipment to study for turret/tag board layouts would be older classic test equipment from such as H.P. or Tektronix.
Audio requirements aren't typically as demanding as a scope but it's quite a thing of beauty to study an old Tek scope and learn a few things.
Morgan Jones has a companion book to his Valve Amp theory book which talks about actually building amplifiers. Both books are worth buying if you haven't got them.
A good simple place to start with on a layout is to group the signals together as they are used on each stage. Try to visualise the current flow as it happens in the stage and give it a nice short AC and DC loop to follow. So, for instance, don't make it go to the other side of the turret to a Kathode resistor or the valve socket to make connections and complete the loop. Maybe redraw the schematic with this info indicated on it.
Some people actually draw their schematics with the signals grouped already.
If we take a hypothetical and simple triode gain stage - the loop would include the H.T. filter/decoupling cap that feeds the stage, the anode load resistor, the grid leak resistor of that stage, and the Kathode resistor with its bypass cap if there is one. Also the input transformer secondary wires if there is a transformer. And of course, the valve itself. So you would group those parts together on the turret close to the valve socket and have all the bottom ends (grounds) of those parts connected together with a bit of busbar wire. The same with the H.T. as well. A lot of older audio gear had all the filter caps (and kathode bypass's) right next to the power supply in multi-section caps and just ran wire back and forwards. Better to not do this if you can avoid it. Also, a lot of older valve stuff used the chassis as the ground returns (LA-2a) which you should also NOT do.
Things like grid stoppers should be wired directly at the valve socket and there's no reason you couldn't wire a stage's coupling/blocking cap directly from one valve socket to the next if it's not too big.
Draw a realsize picture of the turret on your computer, print it out and play with the components on that first to avoid mistakes or to try different things.
Have fun, I do
