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While turning the pedals (backwards if you run a freewheel or any direction if youre fixed), run a light bead of lube along the inner circumference of the chain - the side that will contact the chainring(s)/sprocket(s). Don't go overboard, just enough that will provide a fine coating once the drivetrain has cycled completely through. Over oiling is what will attract more crud more quickly.
All of it. Everywhere. Pour it on. Try to get it all over the chainstay, cassette, rings - everywhere possible.
Your mechanic will thank you.