just 'have your wits about you,' I'm kind of presuming that you are visiting without a scouse accent ? in which case nobody will probably even realise you are a blue (unless you are attending in a morph suit or something), if it's city centre drinks then Canal Street is the place.
If staying in manc for the evening frivolities then there is a network of canals & pathways, however using them for short cuts isn't advised (look up 'The Pusher').
They are a bit of a different breed around Manc/Salford & if you are wearing the latest fashions or good trabs they'll be on to you straight away.