The report aims to give advice on parameter derivation for standard and advanced constitutive (soil) models, with focus on soft soil models. The soil models concerned include several strain-hardening models that are commonly used by geotechnical practitioners, installed in the Plaxis finite element (FE) suite, such as the Soft Soil model and the Hardening Soil model. These are referred to as the standard models. In addition, an advanced creep model developed at Chalmers, soon available for practicing engineers, is considered. Firstly, key features of the models are introduced, highlighting the main differences of the models. This is followed by recommendations for testing needed for reliable model parameter determination. It is highlighted that whilst for some of the models the determination of model parameters can be done easily based on typical Swedish site investigation and lab testing, for some models, this is not the case. Finally, advice on laboratory testing programme when intending to use geotechnical FE analyses is done.