SC is by far the toughest section to master for non - natives. Having said that your hard work will be rewarded the most in this section. You will have to develop a bulldozer attitude to steamroll the concepts. Fear the complexity and the section will continue to elude you. I also used to think that the number of questions are less - but let me tell you that was an excuse on my part for not being thorough enough with the concepts. The key is not the number of question , but developing extreme familarity with the concepts by reading and re-reading the book till you can teach the concepts to your friend.
Enough Gyan, now how to approach SC.
1.) Be patient with SC - it is something that needs 1 month at the minimum (for normal folks).
2.) Keep a few supplementary books for refering the important definitions - Aristotle SC Grail, Wren & Martin, Kaplan Verbal
Foundation. You can also refer the end of MHSC book for definitions.
3.) Make notes for all the examples in MHSC that are not intuitive to you.
4.) Read the MHSC book several times(4-5 times)
5.) Focus on the non advanced section of the book first.
6.) Be merciless in your work with this book - be it a boring chapter of IDIOMS or whatever.
7.) Try Manhattan Review
Turbocharge Your Verbal - This has a collection of 250 SC problems. Try to solve 100 of them before jumping to OG12
8.) Jump to OG12
and solve each and every question and make notes for all the concepts that you have not seen in MHSC or one that are new to you.
There are 2-3 more steps to achieve a total mastery to SC , but will take that later.
It's easy to say you can't do it , you are not good enough.
It's much harder to step in your shoes and work to the point of achieving it.