Ditch the bottle cages and bolts altogether and stick the bottles in your jersey pockets.
Ditch the bottles too and stop at a 7-11 for a drink every now and then.
Fill your tires with helium.
Trim your brake and derailer cables right up to the clamp nuts.
If you use SPD pedals, remove the clips on one side.
Grind new brake pads down to half thickness.
Remove the rear brake altogether.