The latest years have seen great advancements in developing quantum computers, yet scientists and engineers will have to resort to NISQ (noisy intermediate-scale quantum) solutions in the near future. This requires quantum protocols and algorithms optimized for these architectures. We will design so-called variational quantum algorithms for quantum-gate-based architectures, with which we will solve optimisation and machine learning tasks. For adiabatic quantum architectures, we transform certain, mainly combinatorial optimisation tasks into quadratic unconstrained binary optimisation (QUBO) problems.