The nature of the main ingredients of the standard model of cosmology, dark matter and dark energy, remains a mystery. Better observations are needed, where the biggest advance will come from precise measurements of the growth of large-scale structure. In principle, the next generation of imaging and spectroscopic surveys provide an impressive amount of information about the universe, but extracting this information is challenging: a wide range of observational and astrophysical complications prevent a direct, simple interpretation. To fully exploit the potential of these data, we need to improve our understanding of how galaxies populate dark matter halos. I will make the case that this is possible.