I'm currently doing around 90-100miles a week road riding, each week I am trying to push larger speeds and constant speeds on hills.

As I am of large build (16.9stone) I would like abit more stamina.

What would be a good way of doing this?

Are their any supplements or diet advice which would help?

Also one last thing.

Fluid consumption, what would be an advisable consumtion for a 30mile ride?

Reason I ask is I only drank 1 litre of water and never felt de-hydrated?