The list that appears in game is created at random with a few determining factors. One of these factors is activity. The more active your corporation is, the more likely you are to appear on the first page. Make sure that all of your corporation members are logging in every day to chat, send loyalty points, do projects and generally play the game! This will increase your chance of being on the front page. It is important to note that any inactive players will be pulling down your average, one very active player cannot make up for an inactive one. So, if you have any players that do not participate, it would be best to remove them from your corporation.
You might also want to try advertising outside of the game. A lot of players post on the official Syktopia Facebook page, found here.