I also have 4 months for the GMAT exam, but I stated 1 month earlier, dont know when you did, but you could get a rough idea from this.
At first I knew that I am stronger in quant in comparison to verbal. I started doing some random questions on GMAT forum, and you have books also, and after around 3 weeks I got to know my week areas in quant, now Im focusing on them for the past 3 days, and will continue to work on them till next week.
So, you should look the topics index in your book, you can do it without first doing random questions like me at firsr and them jumping at topic wise weak areas. I suggest you to go topic wise, and since you have given a mock, I suggest to you go for the weaker topics, like the entire topic. Work on them for 2 weeks.
For verbal, you should study atleast 1-1½ hrs a days, depending on your weaker topics. In my case sentence correction is the most time I need to give, then to critical reasoning and least to RC.
You should also put your weaker area at first with stronger at the end, like I have written.
And books that you have are goog ones, read their basics again and again.
Best of Luck.
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