This lecture introduces new routes for magnetic nanostructure fabrication and characterization. First a practical approach for large scale metallic nanostructure fabrication via template assisted self-assembly is presented. PS-b-PMMA diblock copolymer films with long-range chemical surface patterns serve as templates for preparing highly-ordered arrays of magnetic nanostructures (dots, antidots and nanowires). In-situ x-ray studies reveal the structural formation of the nanopatterns and their magnetic evolution during growth by sputter deposition. Further, a new deposition technique is shown which allows us to engineer and stabilize almost arbitrary magnetization depth profiles within ultrathin magnetic layer systems.