Final answer:
The first thing to do if your boat runs aground is to make sure no one is injured and check for leaks.
Step-by-step explanation:
The first thing you should do if your boat runs aground is make sure no one is injured and then check for leaks. The safety of the passengers should always be the top priority in such situations. Once you have ensured everyone's well-being and addressed any potential leaks, you can proceed with other necessary actions such as shifting the weight to the point of impact or using the engine to reverse or move forward depending on the specific circumstances.