We have developed an aqueous chemical solution deposition platform for piezoelectric oxide thin films based on an in situ characterization toolbox to gain knowledge about the nucleation, growth and formation mechanisms during the formation of the films. This knowledge gives us valuable information to design oxide films with desired properties. Here we present aqueous chemical deposition as an environmentally friendly and highly flexible route to tailored and reproducible synthesis of ferroelectric oxide thin films. Aqueous chemical solution deposition of phase pure oriented piezoelectric thin films demands strong control of processing parameters. An in-situ cell for synchrotron X-ray diffraction studies of the annealing and crystallisation steps during the aqueous chemical solution deposition was used in combination with in situ IR spectroscopy and total scattering to understand the evolution of the films during heating. We discuss how the knowledge about nucleation and growth can be used to design the optimal procedure for fabrication of BaTiO3-based, K0.5Na0.5NbO3 and SrxBa1-xNb2O6 thin films oxide films with desired properties.