We discuss several mechanisms useful in control of pattern formation in copolymeric systems. Chemically patterned substrate is shown to induce ordering in confined diblock copolymer melt. The strength and range of this ordering depend on interfacial interactions and surface feature size. Electric field is effective in aligning a sample in a desired direction by the "dielectric mechanism". We explain how this effect can be exploited in certain situations. We consider the new effect of dissociated mobile ions in a melt in electric field. Orienting forces in these non-equilibrium systems are calculated and are found to be important to alignment. Some morphological changes predicted to occur are illustrated.