Bickpacking and Hiking Hygine
Cleaning
Maintaining good hygiene is very important.
Pay special attention to your feet - even if you are on a bike - they are your only option for movement should you break down (suffer a "mechanical"). Equally important if bikepacking are your hands, bum and your bits which maintain contact with the bike all day.
Be sure to take the time to wash. Even if you are not smelling you will still have some salt build-up which can cause sores, especially on contact points on bikes or with backpacks. I take 2 flannels in 2 ziplock bags clearly marked as "body" and "bits" and use accordingly - wetwipes also work but I'd encourage you to be as eco friendly as possible and use flannels with biodegradable soap if/when you can. Clean every day straight after you make camp - I do it while my water is boiling.
A tactical, planned hotel/B&B stop can do wonders for moral - knowing you'll have a warm shower to properly feel clean and a nice warm bed is a great motivator.
Pee
Try and use proper facilities where possible. Otherwise, keep away from water (30meters+), where possible "pack out" (keep and bin/flush later) tissues.
Poo
My best advice is to plan to poo whenever possible. Treating yourself to a cafe/pub lunch? Poo. Splashing out on a B&B? Poo. Passing a wilderness portaloo or tourist info centre? Try. a. poo.
Carry tissues wherever you go, and if absolutely necessary carry a trowel and dig a hole for your poo and "pack out" your tissues (keep and bin/flush later) using some supermarket ziplock bags. i.e. these.