Torque and smoothness
Are your friend when carring passengers. so you'll need a big capacity bike to begin with.
Try to avoid too many gear changes. unless that is you like being repeatly headbutted?
have a set of hand signals prearranged, thumb up thumb down works well.forget microphones and such not, i find the screaming puts me off my riding!
Good Grab rail (see headbutting).also good for protecting the wedding tackle under extreme braking.
up the preload on the rear shock , otherwise your sports bike takes on the handling off a dodgy shopping trolley
good riding Gear for you passenger, they generally come off worse in an crash, give them yours if it comes to it!
otherwise if i haven't put you off, take the pillion as it adds a certain spark to riding, more of a shared experience, and also good for the ego (my brother often tells the tale of Evesham to Hereford, strange that was the last time he came on the back).
Just remember all that extra weight changes how a bike works, and to get the best out of it, the pillion needs to know what your doing, so never going to come with one ride. don't try and scare them and given time having a pillion can be very rewarding(someone to buy the tea for a start)