This review article is concerned with three topics important for the construction of four-dimensional models of particle physics in the context of type II String Theories. The first of the three topics deals with the tadpole cancellation conditions and the cancellation of chiral anomalies for type IIB orientifolds with orientifold three- and seven-planes. The second topic is related to non-perturbative effects originating from D-brane instantons. In particular, in the presence of a realistic particle physics sector, a chiral zero mode constraint for contribution of instantons to the superpotential arises. The third topic is about moduli stabilisation in type IIB string compactifications. Two scenarios, the KKLT and Large Volume Scenario, are reviewed and a model for the latter scenario with the chiral zero-mode constraint taken into account is presented.