"Making Law Review" is a very different process depending on your law school. Most schools offer some combination of "grading on" and "writing on" Law Review. My school largely combines the two by giving 50% of the points for grades, and 50% for your score on the spring writing competition. Other schools offer students the opportunity to make Law Review by submitting a written article of publishable quality, although this final option may in some cases only be open to transfer students who didn't have the opportunity to participate in the writing competition. Making Law Review is extremely important at middle- and lower-tier schools, where competition for jobs is fierce, and less important at the Harvards of the world where, let's face it, pretty much everyone is going to score an awesome job. Making Law Review is not the same thing as making a Journal. Most schools have multiple journals, but only one law review. As such, being on a journal is not as "prestigous" as making The Law Review. However, at schools with many journals, not making ANY journal can significantly impair your ability to find a job, as employers looking at students from your school will grow accustomed to seeing a journal listed, and will wonder why you weren't able to make a journal.
Making Law Review should be distinguised from Being on Law Review. The former is a highly prestigous honor; the latter is a figurative rock tied around your ankle that prevents you from having any free time your second year (and third if you are a member of the editorial board).