There are many features that are used to identify microorganisms. In general though, these characteristics can be broken into two categories: classical and molecular. Things like cell shape and size, staining behavior, and method of movement, if it moves, would be things to look at to help classify this microorganism. You can also look at the cell structure, what its source of energy is, its optimum pH and growth temperature and range, its oxygen requirements and its tolerance to antibiotics and metabolics. All these factors and more can help identify this new microorganism and determine what it's classification is.