1. Air Max 2015's have a logo fused onto the tongue. Check the quality of printing of the logo and the typeface of the logo, the two letter "A's" should have no cross bar.
2. The Cushlon Air Unit midsole which provides springy impact protection has a large Air Max logo printed onto it. Check that the printing is solid with sharp edges.
3. Air Max 2015's have molded sockliner inserts, check the shape of the sockliners, specifically look how the midfoot arch area curves up to follow your foot arch.
4. Check the style number, usually 9 digits, matches that found on the box. Tip: Do a Google image search for "Nike"+"style number" to check the colourway.
Go to goverify.it for a full 20 point step-by-step guide.