Finding an internship can (will) be stressful for students, so here's some tips I've compiled to hopefully make the task a little less stressful.
Start looking a year and half before you would start
This might seem like overkill, but trust me, you want to do this. There were several internships I missed the deadline for because they wanted all application materials an entire year before the internship started. So if you're starting you final year of coursework in the fall and start looking, you might already too late if you wanted to start in the summer or next fall.
Be aware of deadlines for your professors' sake!
Our music therapy professors are awesome people, but they're also busy. PLEASE give them time to write your recommendation letters. I had a couple of instances of asking for some sooner than their wishes (in our department handbook it was stated to give them four weeks time), and I'm super thankful they did it anyway.
Budget for sending transcripts
Every time I applied for an internship I sent two transcripts, one from my university and the other from a community college I took online classes with for core credit. Honestly I didn't know who to ask or how to find out if I was doing the right thing sending both, but I did it anyway. You should probably not do what I did and check with your school or internship on what they prefer. Some schools give you a set amount of free transfers before they start charging, which is nice.
Do everything ahead of time
Write down the deadlines for everything two weeks in advance. Seriously, do it! Then if something bad happens, like your application took forever in the postal system or your transcript wasn't able to be opened by the recipient (happened to me), you have some dead space to figure it out. Also it looks good on you for having your stuff together and turned in early.
Choose a population that you want, but if it doesn't work out it's not the end of the world
Regardless of where you have your internship, as long as your supervisor is competent, you're going to learn something. Don't sweat it too much if you only want to work in the NICU and you can't get an internship at a pediatric hospital. Your internship doesn't define the rest of your career. I was very wishy-washy on what population I was interested in, and that changed my senior year. I still feel wishy-washy but now I have a lot more knowledge on the pros and cons of each population and am so excited to start my internship!
You can't predict the future
Similarly state above, things can and probably will happen in ways you aren't expecting. Be cool with that. If you could predict every step of your life you would never grow as a person and your life would become very boring!
Lastly, think about logistics
If you get an internship out of state or in a city you've never been to or is far away, that is going to add stress. I'm not saying it won't be worth it, but be aware that moving states away can be very expensive and you should anticipate that. I've known several people who had to sign a lease for an apartment they've never seen, in a town or state they've never been to! Not to say you shouldn't spread your wings and live somewhere new, but be aware of some of those issues. If you want to experience living in a new place and networking in another area, then maybe looking far from your current city or state is a great idea for you!
Observe music therapists
This is a bit of a weird add-on, and I might write a separate blog post about this but observe as many music therapists as you can before and after your coursework ends! Not only will you earn pre-internship hours if applicable, but it will make you a better student, intern, and therapist.