Ive been rolling with traktor to gigs for the past couple of years, come across all of these woes on my travels, heres my 2p :
re: dirty contacts,
Most smaller clubs will have old ratty hardware with crap connections, while the ISO alchohol is a good measure, its not exactly practical. Get yourself a fibreglass pen brush:
https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=fibreglass+pen&tbm=shop
whip it round the contacts and you'll be back up and running in less than 5 minutes.
re: multicore cables,
they are great, and make setting up way, way faster (especially if you label them!) but they are by no means a necessity and will not make your music sound any better or make any connections more reliable.
re: shitty phono's
most of us will have had this at some point, sometimes they can be fixed with a little fiddle, other times there is no saving them. The crucial point with this is to have a backup plan you can fallback on instantly. set up a button on your keyboard to set the decks to internal playback while you debug the problem, keep the crowd happy!
Ideally, get a controller.
I'm not talking about a Kontrol S4, just something small which augments the DVS system nicely. A kontrol X1 or novation dicers are compact and will fit into any booth with the minimum of fuss. They also keep you away from your laptop and will allow you to perform on ANY setup, no matter how fucked.
I've played at gigs before when other DJ's couldnt play because the decks were fucked and the CDJ's were stripped out of the booth for another room. It was all fucked until I setup and played with only a mixer and X1, someone with serato couldnt do that and traditional means were all shot! The black sheep saves the day, go figure.
to be fair, always expect the worse and carry at least one backup.
