Instructions
Keep the Digimon you want to level up in your party at all times. Unlike some RPGs, "Digimon World Data Squad" does not have an "experience sharing" feature. This means that Digimon not in your party will not receive experience points.
Fight in battles often. Winning battles with your Digimon will grant you experience points, which is the only way to level up. As you increase a Digimon's level, the number of experience points needed to reach the next level also increases.
Fight Digimon that are higher in level than you are. As you engage in new battles, you will be able to see the other Digimon's level. If it is between one and five levels higher than yours, you should be able to take it down without too much of a challenge. The higher an enemy Digimon's level, the more experience you will get.
Fight higher-level Digimon until your level is equal to theirs. As your Digimon levels up, the fights will become easier to win. When you are satisfied with your Digimon's level, continue with the main quest.