Study a little everyday, focusing on one subject, ie Factors of Flight, meteorology (toughest for me, don't know why,) Instruments, Rules and Regs. from the FAR-AIM focussing on just the relevant parts for your SEL rating? , Cross- Country, and practical Airport Ops. stuff.
Then the last 3-4 days take the computerized test over and over again and focus on the sections you get wrong.
I went to a computerized testing center that had a Flight calculator built in the testing software. (almost felt like cheating

)
And don't stress, because you will pass.