For a conventional hub with horizontal dropouts (forward facing, no chain tugs) my method is : Bike upside down, 2 x 15mm spanners, wedge shaped piece of wood (custom fashioned) jammed between tyre and lower stay bridge (i.e. behind BB) - force tension with the wood and use the 2 spanners at the same time (grip wheel between thighs) to tighten to "Christ, that should be enough" tension. Remove wood, return bike to standing on wheels - apply 15mm spanner again and use foot to get to "I'll never get this undone again" tension.Hey presto, "That chain looks tight"