This week I got my California driving license back in lieu of my old NY license. California laws are more strict and they make you write an exam before issuing you a license. You only need to answer 18 of them with maximum of 3 incorrect answers. There are tons of sample papers available on Internet to prepare for this exam. I also had to appear for another written exam for motorcycle. There are very few resources for practicing for this exam.
I found this link with few test papers. I did go through all of them and there were many questions from this set. However there were still few questions in the exam which I had no clue about. This exam has 25 questions and you cannot pass if you make more than 4 incorrect entries. I failed in my first attempt and could marginally pass in second. Here are the two exams I took that day (exam1) & (exam2). Hopefully they can help you prepare well for yours.