In this study, linear low-density polyethylene/graphene nanoplatelets (LLDPE/GNPs) nanocomposites were prepared from conventional melt-mixing method and our new approach; two-step premix mixing technique. Indirect mixing technique (IDT) was employed to fabricate a premix of LLDPE/ GNPs in the ratio of 80:20 wt%. The effects of GNPs loadings and the processing method of nanocomposites on the mechanical strength, decomposition temperature, crystallinity, electrical impedance and morphology were investigated. Irrespective of processing methods, the prepared nanocomposites exhibited crystalline structure due to the presence of GNPs whilst the degradation temperature was recorded to be increased with GNPs loadings that signified improved thermal stability. The inclusion of GNPs provided electrical impedance ability on LLDPE matrix as a result from the formation of conductive networks of GNPs. LLDPE/GNPs nanocomposites prepared from two-step premix mixing technique showed better mechanical properties than those of melt-mixing method. Apparently, two-step premix mixing of LLDPE/GNPs nanocomposites promoted better dispersion of GNPs in matrix based on SEM images. Our findings have proved that our new, profound technique of preparing premix before mixing could result in enhanced quality of nanocomposites that are potentially useful in packaging or electronic applications.