Car Wont Start First Try.... Once in a while

So I have a 2011 Mazda 3. Every once in a while the car will not start on its first attempt, but the second attempt it starts no problem. This occurs summer and winter, so its not the weather. It's been happening for a while now, and I recently installed a new batter into the car a couple months ago. Im thinking its the starter or my spark plugs, but I was hoping someone could shed some expertise on this matter. Thanks.