Everything between "I think I want to do ultrasound" and your first day at clinicals. Tick things off as you go. Your checklist saves on this device.
A lot of people find ultrasound by accident. That's fine. Just make sure you know what the job actually looks like before you spend two years and real money on a program.
Programs are often competitive, with more applicants than seats. Requirements differ by school, so always check each program's own list.
Practice these out loud. Short, honest answers with one real example each.
The moment you get your site assignment, do your homework. Walking in already knowing the place makes a big first impression.
You might already know a lot. Come in humble anyway. Every sonographer there was new once, and the ones who keep learning are the ones everybody wants to hire.
Your first weeks will feel slow and awkward. You'll mostly watch, then scan normal anatomy, then start your competencies. Bad days are normal. Every sonographer you meet once struggled to find a kidney.