As you walk, you earn Aglet. How many you will earn 'per step' depends on a whole range of factors, including the earn rate of the shoe you're wearing, its condition and most importantly the WEATHER. (the wear rate determines how fast a shoe wears down).
You can earn a BOOST of up to 5 times your current earn rate that your sneaker earns with the weather.
To check how much your shoe has earned, swipe up on the shoe in the 'Wear' screen, then click one of the tabs (month, week, day, hour). If you want to check you boosted step, click onto any column under the tabs.