Wormlike micelles (WLMs) are a class of self-assembled structures with useful rheological properties. These properties can be controlled by addition of colloidal particles. Specifically, particle addition leads to formation of viscoelastic networks in dilute solutions and enhances the viscoelasticity of semi-dilute, entangled WLM solutions. Particle addition also suppresses shear banding near the isotropic-nematic phase transition. Measurements show that this additional structuring occurs by the direct association of micelles at particle surface. These micelle-particle aggregates increase the compressibility of the micellar fluid, contribute increased viscoelasticity to the WLM network through the contribution of additional network junctions, and suppress shear banding by restricting micellar flow-alignment near the particle surface. Thus, particle addition to WLMs enables the properties of viscoelastic micellar networks to be tuned.