If you wish to take a deduction for the use of your automobile, it is the reccomendation of this firm that you have a mileage log.
Even if you take a percentage of your expenses, rather than the standard mileage rates, your must maintain mileage records in order to figure out your business use percentage.
A mileage log can be in writing or there are devices available that will automatically track mileage for you.
When taking a deduction for business travel, ensure that the travel in question is for a legitimate business purpose. That includes, but is not limited to, a client meeting, income producing property sale or arrangement, or it was related to a professional seminar or education session directly related to your business.