Three-dimensional DEM simulations in shear flow were conducted to understand the influence of various specific features of particle shape - such as aspect ratio or roughness - on granular stress. Various non-spherical particle shapes are formed from linking and/or overlapping spheres. Granular stress at dilute particle concentrations is shown to be a function of the projected area of the non-spherical particle. At dense particle concentrations, the granular stress is strongly influenced by the collision rate and the average impact velocity. The higher the particle aspect ratio, the higher the collision rate and the lower the average impact velocity, resulting in an increase in the granular stress at high concentrations. Decreasing the coefficient of elasticity decreases the granular temperature and in turn decreases the kinetic stress and decreases the impact velocity which decreases the collisional stress. However, the decrease in elasticity and the increase in aspect ratio leads to greater particle packing and, therefore, a greater collision rate at higher concentrations resulting in similar stress values for high and low elasticity. Increasing friction leads to a decrease in the granular temperature and in turn a decrease in the kinetic stress and the average impact velocity, but there is a much more significant increase in the collision rate at higher concentrations when the aspect ratio is increased leading to a rather large increase in the granular stress.