But hey, please keep in mind that I'm just one person and this is based on my experience. I invite other librarians to add to this post in comments! What advice do you have for people just starting their MLS program?
1. If you have some flexibility as to what school you can attend, look at their youth-oriented course offerings. Although any accredited school should have pretty solid basics (reference, collection development, etc.), different schools have different offerings when it comes to youth services. That said, I attended a school that didn't offer an astounding variety of youth classes and I think I came out okay. :)
2. Think about whether you might want to be a school librarian or a public librarian. If there's any chance you might want to work in schools, I'd recommend going the school media route. I'm sure some of my school media readers can weigh in on this more, but generally school library positions require that you have done student teaching and have a teaching certificate. A straight-up MLS program doesn't include that stuff. So while you can be a public librarian with a school media MLS, you may not be able to work in schools with just your MLS. This is a great question for your advisor or admissions counselor since I do not have a lot of knowledge about school media programs.
3. My best advice for making yourself marketable with your MLS degree is doing an internship while you're in school. Not only does this give you library experience to put on your resume (and it should be in a department or program relevant to what you want to do when you graduate), it helps you make contacts who will be references for you, and it'll give you an idea as to whether you like doing it! I interned in the children's department of my local public library while I was in school and I'm 100% certain that that's what helped me line up a job.
4. If you don't have the opportunity to do an internship, volunteer! If you want to go into youth services, I'd recommend volunteering with children. Volunteer at your local library, Boys & Girls Club, Big Brothers/Big Sisters, homework help, tutoring, your religious Sunday School or childcare, Headstart... One thing that library supervisors absolutely look for in applicants for youth services jobs is some kind of experience with youth. We need to make sure you're comfortable working with kids (and if you don't have experience with kids, you should probably make sure you're comfortable working with them, too!).
5. The job market's a lot different now than it was when I graduated at the tail end of 2006. But what I think was most helpful about my job search is that I didn't limit it geographically for my first job. For my first job, I was willing to go anywhere and then hopefully I could move closer to my hometown once I had some experience under my belt. I applied for jobs in Arizona, Massachusetts, Virginia, Florida, Illinois, Ohio, North Carolina and maybe more... I ended up moving to a suburb of Chicago and then a few years later when a job opened up near my hometown, I was able to move back!
6. If you're not geographically flexible, I'd advise you to be flexible about the type of job you'll accept. Maybe your ideal job would be in a children's department but your local library's got a job open in circulation. A lot of times it's easier to move around within the library once you've got your foot in the door. And it's always easier to find a job when you HAVE a job.
And that's my advice. Librarians, please weigh in with your advice in comments. Potential librarians, let me know what questions you have about library school. And please feel free to contact me any time at firstname.lastname@example.org.
Edited 3/21/12: Links to other advice posts have been moved to my So You Want to Be a Librarian page in order to make them more accessible. If you accessed this page from elsewhere, you might want to check that out!