This thesis is devoted to the study of two major scenarios of physics beyond the Standard Model (SM), namely TeV-scale supersymmetric models and models with dynamical electroweak symmetry breaking. For the supersymmetric models, we will concentrate on supergravity-mediated grand unification models. We analyze the mass spectra and collider signatures for minimal supergravity (mSUGRA) models. We also study benchmark models with non-universal masses in the gaugino sector. We are particularly interested in some collider signatures that can be discovered in the early LHC experiments with center of mass energy of 7 TeV in operation in the years 2011 and 2012. In addition, we will discuss the dark matter implications for these benchmark models. For models with dynamical symmetry breaking, we study prospects for the unification of different gauge groups.