Meet people before Slimelight
Dance floor 2 on level 3 opens at 11 pm, whereas dance floor one on level 2 opens at 10 pm. Although some people do go elsewhere beforehand, the fact that Slimelight level two is open from 10 pm with two drinks for the price of one before 11 p.m, means that it has become popular itself. However you could always try the following:-
'The Purple Turtle', Essex Road, Islington :
About a 5 to 10 minute walk from Angel tube, this packed bar with a fairly good (but techno-ish) juke box was one of the places to be a year or so ago, but I'm not sure if many Slimelight people go here anymore. Same directions as for the York below, but just keep on going past the York, and make sure you veer to the right into Essex Road (you should walk past a Barclays Bank). The Turtle will eventually appear on your right hand side.
'The York', High Street, Islington :
This is about 30 seconds from Angel Tube, and is sometimes populated with net.goths from news: uk.gothic.people, and other Slimelighters - especially after 10 pm. This can be a good place to find someone to sign you in if need be. From Angel underground station, turn right, walk past the huge Royal Bank of Scotland (which will be on your right), and the York will suddenly appear on your right. Again, it seems now that most people just go straight to the club on arriving in Islington.