For Hip Hop and R&B you'll likely want a tight mix that sounds great in mono. For more information on why this matters and how to do it you can check out this blog post I wrote about my time working with Dr Dre:
Aside from that you'll want to make sure you leave enough headroom for the mastering process (-3 to -6 dB of headroom) and use a lower stereo width setting, to ensure the low end sounds crisp in clubs and venues.
The ideal loudness setting depends on the track, but usually the loudest setting you can make that still sounds good is what you'll want.