The production of liquid fuels from lignocellulose-derived platform molecules has attracted much interest in recent years. Platform molecules mostly have a shorter carbon chain length, compared to liquid fuels, which have a typical chain length varying between 4 and 25 carbon atoms, whereas aviation and especially diesel fuel have a carbon chain length exceeding 10 carbon atoms. For this reason, some carbon chain length increase reactions are required. In this article, carbon chain length increase reactions are compared for typical lignocellulose-derived platform molecules. The focus is placed on the ability of the molecules to participate in self-condensation reactions in a controlled manner. Hydrogen plays a key role when producing fuels from platform molecules. Hydrotreatment is applied not only when converting the products from a carbon chain length increase reaction into hydrocarbons but also for modifying the functional groups of the model compounds and, thereby, their reactivity.