Try to cut the low end out, and the low-mids. Most vocals on samples dont live in these frequencies ranges. Everyone has the preference, so just experiment until you find the sweet spot.
Oh yeah, try a paragraphic or parametric EQ, these usual have all or most of the frequency ranges (31Hz to 16KHz). If you have a hardware mixer with sweepable mids (Knobs for the Low and High Mid range frequencies) you can run your sample through it and see how it soundz.