Direct visualization is among the best ways to elucidate physical phenomena. Tracking the motions of particles in water by video microscopy, for example, has consistently revealed insights about phenomena such as the glass transition, coffee rings (or lack thereof), and crystallization that are otherwise challenging to understand. This talk will utilize direct visualization to understand the role of size, shape, and inter-particle interactions between colloidal particles and substrates in affecting their self-assembly, structure, and dynamics. Specifically, I will explore the nature and correlations of structural relaxation across timescales in colloidal supercooled liquids and glasses comprised of binary-sized colloidal spheres. I will show how a small tweak in colloidal particle anisotropy (shape) affects reentrant glass transitions. Lastly, I will show how short-ranged depletion attractions between particles can be utilized to achieve site-specific colloidal crystal nucleation and growth on surfaces. In both the sections, I will also delve on some open problems for future investigations.