Even if your home office is serving a dual purpose, you should still make a wholehearted attempt to let your personality shine through. After all, your away-from-home office probably sports all the neutral coloring and boring furniture you can handle. Select artwork or accessories that mirror your interests but that guests will enjoy. For example, if you're a music buff, frame some vinyl record album covers, tour posters or other memorabilia that'll inspire you while you work.
Don't be afraid to play around with color, either. Consult a few design sites or television shows to learn how to cheaply and effectively select paint or décor that will complement your guest and office furniture. By mixing and matching neutral and vibrant colors, you can easily create a space that anyone will enjoy spending time in, even if conference calls are involved.