The makers of the Spanish Praxis offer sample test questions for free with answers to follow. Take the sample test and see how you do. If you do well, then you'll probably do well on the Spanish Praxis. (?) If you don't do well, then calculate the sections with the most errors and use that as your guide on what you need to work on. You will find a variety of high quality reviewed sources that you can use to start reading authentic materials daily and/or listening to authentic speakers daily at www.cs-spanishnews.blogspot.com.
From the ETS link below you will find the following approximate breakdown of the test:
Listening: 30 questions (26%)
Reading: 30 questions (26%)
Culture: 15 questions (12%)
Writing: 18%
Speaking 18%
Prepare for all sections of the test well, but keep in mind that listening and reading are a little more than 50% of the test. That is significant. These skills must be strong. The best way to improve these skills is to start reading and listening to authentic Spanish media daily. You probably already know this, but just a reminder; "authentic materials" are written and spoken media that were designed for native speakers of Spanish, not for second language learners. This is a critical distinction because you will be required to understand "authentic Spanish" on the Spanish Praxis. This blog was designed to help teachers and students find high quality sources of authentic Spanish for lessons and student practice. I hope you will use it to prepare for the Spanish Praxis. Have fun exploring, reading, and listening to all the authentic materials provided in links on this blog. Check out a different one every day! Here is an example of the Argentina BBC link to the left on this blog; first you will see English, but when you scroll down you will see links to authentic newspapers, television, and radio in Argentina. It doesn't get much better than that!
You will know after you take the sample test on the link below where your weak skills are. You can't test your listening skills though on this sample test and it's quite important, so buy their prep book because it has a listening practice component. At least you'll know ahead of time if you are strong or weak in that area. Don't give up if you don't pass the first time. ETS will provide you with a breakdown of where you made mistakes by category, so you will know where to work harder for the next test. Here is the ETS link showing you the breakdown of the test and it includes free sample test questions with answers.
http://www.ets.org/s/praxis/pdf/5195.pdf