Clinical practice guidelines are most often published and updated by professional organizations. For example, the National Comprehensive Cancer Network® (NCCN®) offers clinical practice guidelines on the treatment of various types of cancer (linked below). If you already know the organization who published the guideline, you may find it most easily by going to their site or by searching PubMed.
Search guideline collections to find guidelines based on the disease state or your research question. Depending on the topic, some will work better than others so you may need to try more than one if your question is more unique. Not only does this method ensure that you see guidelines from other organizations you may not have thought of, you should also find it easier to access the published articles in the USF Libraries collection.