GeSn alloys have emerged as a promising material for group IV light sources because alloying Ge with Sn increases the directness of the bandstructure, thus improving the efficiency of light emission. Despite several years of progress in GeSn lasers, however, the integration of such lasers into practical applications still faces challenges such as high threshold, low operating temperature, and large device footprint. In this report, we address these challenges via each of the studies containing thermal management, defect reduction, and nanowire growth approach. First, we demonstrate improved lasing characteristics including reduced threshold and increased operating temperature in GeSn microdisks directly sitting on Si, which is allowed by the enhanced thermal management over the conventional suspended microdisks. Although there is a concern about poor optical confinement of the sitting approach, we confirm the simultaneous achievement of excellent heat dissipation and superior optical confinement from the microdisk released on Si through experiments and theoretical simulations. We also demonstrate a decreased threshold in microdisk lasers fabricated using a high-quality GeSn-on-insulator (GeSnOI) substrate. Photoluminescence measurements show that the reduction of defects in GeSnOI leads to enhancement of spontaneous emission and reduction of the lasing threshold. Lastly, we present the potential for GeSn nanowire lasers having smaller footprints by observing clear cavity resonances in a single nanowire grown by a bottom-up growth approach. Our demonstrations provide guiding principles to push the performance of GeSn lasers to the limit towards a realization of practical group IV light sources.