Hey guys... saw this post and thought I would add some advice based on the application process I went through last year.
Here are the things I think are most important when applying:
1. APPLY AS EARLY AS POSSIBLE. I cannot stress this enough. I applied very late in the process (I mean days before the deadline) and as result I ended up on a lot of wait lists. The fact is, as schools send out more and more acceptance letters, their standards increase. So the earlier you apply the better chances you have at acceptance.
2. Figure out your weaknesses and find ways to compensate. The four pillars of the application are your grades, your GRE, your letters of rec, and your essay. If your grades aren't good (and honestly they don't really need to be for grad school), get a decent GRE score, cultivate good letters and WRITE YOUR HEART AND SOUL INTO THAT ESSAY.
3. Letters of Rec can be very helpful. I made sure to develop relationships with professors well in advance of this requirement. But even if you haven't, the key is to show them just how passionate you are about the profession and your future. Professors are there to help you succeed, if one refuses to write you a good letter (and it's okay to ask if they're going to write you a good letter) then find someone else to help you.
4. The essay. It sounds easy. It's not easy. Start writing a couple months before the due date and constantly revise and edit it. Make sure you have as many people as possible read it. You want it to be easily understood and not boring. DO NOT JUST WRITE ABOUT YOUR ACCOMPLISHMENTS... the point of the essay is to show how what you have done has prepared you to learn and grow and be a professional. Think abstractly. I bought a book to help me with this...
http://www.amazon.com/Graduate-Admissions-Essays-Fourth-Edition/dp/1607743213
5. Contact a professor at every school you are applying to. Make sure to review their work first and cultivate an interest in them. They can give you suggestions on getting accepted to their school and in some instances they've been known to assist in making the decision to accept you. Plus if you end up going to that school you're a step ahead of everyone else.
6. If you are wait listed, FOLLOW UP! Show them that you are motivated to go to that school. The second I was informed I was on the wait list I sent a letter telling them I was honored to be considered, I was still very much interested in their program, and sent them an additional letter of recommendation. Also... this is when networking pays off. If you have been talking to a professor there, ask if they have any ideas how to push the scale in your favor. REMEMBER BEING WAIT-LISTED IS NOT THE SAME AS BEING REJECTED. Think of it like a scale, with acceptance on one plate and rejection on the other... perfectly balanced and canceling each other out. Do anything you can to add to that acceptance plate and push the odds in your favor. Find someone who either graduated from that program or knows people there (hit up all your professors) they might offer to help you out or at the very least offer good suggestions as to how to get in.
I started out last year with a 3.1 GPA, a BA in Speech & Hearing Sciences and a 315 on the GRE (V:164/M:151) When I applied last year I did just about everything wrong. I applied way too close to the deadline and as a result I was wait listed at a lot of places. Luckily I was told about the importance of networking and was able to get myself on the acceptance list. Now I'm a first-year AuD student at Northwestern!
PS - Also remember that if you are applying through CSDCAS, they are ridiculously slow. So you should have your app in about a month earlier than the written deadline!