Hip hop vocals...
Good LD condenser
Track 1: Main Vocal
Track 2: Overdubs
Track 3: Overdubs 2
Record the 1st verse. Go back and on another track have the rapper either double the whole verse (not always possible, depends on how well they know their stuff... also depends a lot on the style of the rapper as well to sound right.) Or (more often) double certain words or phrases. Mix this track lower than the main verse 3-6db.
The 3 track is for ad-libs that are also kept lower in the mix. This track is optional. Usually, it's there to add high energy chatter in the background or triple certain words that are already double tracked.
Lots of compression.
Little to no reverb.
I record the hook/chorus on different tracks so they can be effected/eq'd differently. (Often rappers like to do the hook once, then have it pasted in every other time)
With pro rappers, the first vocal track is referred to as the "ghost" track. After the overdubs are recorded, the rapper goes back and retakes his main vocal. With the overdubs playing while he raps, it's easier to get "amped" or deliver a better performance.
A good trick is to keep the verses all panned center. Then double the hook and pan it hard L/R. You may need a third part in the center to even it out and make it less obvious. This "opens" up the chorus and makes it sound bigger than the verses.
A pop filter is a must. Energy is usually the most important aspect of the vocals. He/she has to deliver a confident, high energy performance or it'll suck. (90% of the time)
If it doesn't sound big, add more vocal tracks until it does.
Adding more bass is usually a good idea.
Hope this helps,
Chaz