... I actually have an old 'ninja warrior' handbook thing that explains some of the more advanced concepts of some of this. A lot of it will seem pretty obvious.
- Avoid sight by obscuring direct line of sight
-If you cannot avoid direct line of sight, attempt to wear something that camouflages you in the environment you're in.
-If that isn't at all available, look like you belong in a place (ninja got away with all sorts of shit by basically dressing like cooks / housemaids / janitors etc).
-Acting like you belong in a place is important for maintaining the previous deception.
This is just retardedly obvious things that I've remembered off the top of my head. When it came to combat a lot of ninjitsu was predicated on oblique strikes and fun slight of hand stuff - where they obscure your vision by throwing sharpened coins at your eyes then stabbing you somewhere else, or by spitting needles at your face and stabbing you etc.