There are a few great interior design ideas for very small one-bedroom apartments. One idea is to use light colors throughout the space to make it appear bigger. Another idea is to use mirrors to create the illusion of more space. Additionally, using multifunctional furniture pieces and carefully selecting them that are proportionate to the size of the space can also make a big difference. Finally, make use of vertical space by adding shelves and incorporating plenty of storage to help keep the space organized.