Read a book, study some questions and you'll be fine. Be sure you know all the syntax, rules and DEFAULT values for defining and using sequences. It’s hard to know which functions the test will quiz you on, but be familiar with the basic ones including, but not limited to: TO_CHAR, NUMBER, SUBSTR, UPPER, LOWER, NVL, SUM, COUNT, DISTINCT. I'd also be interested in any opinions regarding necessary formal training, education, certifications, etc.