Fill your tires with helium!

Use purified water in the bottle to remove "heavy metals".

Don't put those little closure caps on the ends of cables.

Measure the exact chain length you need and not a link more.

Sew a flag holder into the chamios of your bike shorts and ride with no seat. just let the seat tube insert into the flag holder.

Chop every third tooth off your chainrings. It will still work ok.

Components do not need the little stickers or logo inserts that identify them, take them off.

Do not use handlebar tape. Just secure the cables with electrical tape and ride with padded gloves.

Polish all the paint off your frame as it is only added weight for appearance.

Last but not least, get rid of all barrel adjusters and just tune your bike after every ride using a wrench.

This will reduce the weight of your bike by about a pound.