More than anything, the rhythms in Afro-Cuban basslines gives them their distinct feel - lots of 3+3+2 type rhythms and whatnot, often using patterns that don't fit into one bar. The notes don't matter as much, but you can't go wrong with roots and fifths (although you can easily throw in other notes to taste).
Melody-wise, I find that the melodies tend to be more simple and repetitive to fit in that style (or at least specifically the African feel - Latin music has become kinda inseparable from Latin-jazz, which is much more lenient in melodic content, imo).
Other than those little tips and hints, try to make sure everything either adds to the pulse or doesn't interfere with it, the rhythmic content is very important with this kinda stuff, imho.
Scale-wise, the above mentioned Phrygian, or the 'gypsy scale' (essentially the same as Phrygian, but with a major third) are always good, but I think there's plenty of flexibility in this area.
Last edited by Maraki : 09-25-2013 at 07:34 PM.