Next step after passing OCA exam is to prepare and take OCP one (1z0-804). You'll need this to become an Oracle Certified Professional.

Preparation for this exam is almost the same as for the OCA one. I still highly recommend reading study guide by Kathy Sierra and Bart Bates - OCA/OCP Java SE 7 Programmer I & II Study Guide (Exams 1Z0–803 & 1Z0–804), the second part of it which is related to the 1z0-804 exam. Also there's an official Oracle tutorial for this exam as well. Combine your reading with writing code. Practice will help you to better prepare for the exam and to train your skills.

For this exam there's also a very good mock exam from enthuware. Again it'll be your best invested 10$ for exam preparation ;).

Registration and actual exam are exactly the same as for 1z0-803, so if you are interested in this check my previous post. This time though, you will receive not only a printed certificate but a nice plastic card with your name on it :)
But being certified in Java 7, when there's Java 9 coming soon, is not good enough :). So I also took an upgrade exam to Java 8 OCP. Keep in mind that you can go for Java 8 certifications right away, rather than taking Java 7 ones and then an upgrade exam. 

Those who are interested in the upgrade exam (1Z0-810) though, should learn new features introduced in Java 8 to pass the exam. Here's a list of topics covered by exam:
  • Lambda Expressions
  • Using Built-in Lambda Types
  • Java Collections and Streams with Lambdas
  • Collection Operations with Lambda
  • Parallel Streams
  • Lambda Cookbook
  • Method Enhancements
  • Use Java SE 8 Date/Time API
As you see all of them are based on lambdas, streams and new Date/Time API. I find Java 8 Lambdas book by Richard Warburton very useful for these topics. It has all you need to know about lambdas and streams. As for the Date/Time API I think reading official documentation and having some practice is more than enough. Enthuware provides a mock exams for 1Z0-810 as well. 

If you are successful in your exam (and why you shouldn't be???) you will receive a printed version of certificate as well as its digital version, a plastic card and a badge:

Hope this will encourage you to get certified ;) 

To be continued...