First and foremost, talk with your college counselor about how to handle each individual wait list situation.
Being on a college’s wait list is stressful because there is no specific timeline when you’ll hear your final decision. When on the wait list, you’re waiting until some undetermined time after May 1st to see if spots open up in the class. In the meantime, you need to make other plans. Of the schools where you’ve been admitted, you must move forward with accepting an offer of admission and submitting an enrollment deposit. You can’t count on being admitted off of the wait list somewhere, so make sure you have a “home” for next year.
To hold on a school’s wait list, you must actively confirm with that school that you want to remain on their list. Generally this is done through an online portal or website. Follow instructions for submitting updated materials like grades or other information. Also, you should strongly consider writing to the school to express your level of interest in attending and why you want to go there. Again, please see your counselor for help assessing each situation.