Missions include collecting a specific number of coins, jumping a certain number of times, picking up specific power-ups, and more. You can see your active missions by tapping the Missions button at the top of the main menu. If there’s a mission that you just cannot do for whatever reason, then you can skip it in the shop for a certain number of coins, depending on what level you are on. Your multiplier will still go up like normal if it is the last mission that you need to level up.
You can upgrade these powerups by spending coins that you earn on runs. Increasing the effectiveness of these powerups can dramatically increase the amount of coins that you earn when you are using them. Upgrade your Coin Magnet and Jet Pack first. This will help you early on in the game as you earn coins to unlock more upgrades and complete missions. Once your Multiplier is close to 30x, start upgrading the 2X Multiplier powerup. This will really start to significantly boost your scores. [2] X Research source
Moving forward is one of the two primary ways that you earn score. Hoverboards ensure that you keep moving forward, and your score keeps increasing. Have 600 to 900+ boards. Use them when your character already runs too fast for you to handle.
Only use keys when you hit something without a board, at 500k+ score.