Its all about trusting yourself.
Most people I have practiced with have been able to master LG and RC with enough patience, so they don't freak out about them anymore, and just do it. No one ever scores less 2-3 on either section, and rarely between them.
Same with Logical reasoning, although due to its varied content it seems to take more time. But with enough practice tests that say 170, you will not stress out, you will assume 4-8 logical reasoning mistakes, and no more then 2-4 games/RC, if you miss 10 you get at least 170...
Yes its possible you will bomb, but with the mentality above, the improvement I have seen is CRAZY. Most ppl from 140 first diagnostic to all 165+ on most practice tests. Don't think about the test as random, just do it like a robot.