I applied to eight schools this year. seven out of those never cared about TOEFL but the last one wouldn't budge even after I pointed out to my GMAT verbal of 40, an A in English at University level and over 16 years of education in English.. So I had no choice but to take the exam. I took my exam on 4th March and got the score today, 14th (in 10 days time, not bad).
I don't really have much to say about my prep strategy actually. Like you'll read in the debrief of other TOEFL takers,if you've done well on GMAT verbal, you'll do well on the TOEFL too, provided you are aware of the test contents and structure. I did ETS sample questions and a couple exercises of each section from Barron's. Both are good material but they will not score your test. Neither will they record your answers for listening or speaking questions. ETS sample though, does provide sample answers for the L and S sections.
You don't really need to sweat the exam. Just be aware of the structure of the test and do 2-3 exercises (Of course, the more the better but 2-3 sample questions from each section should be enough if you've done GMAT verbal). I would recommend that you take your TOEFL after your GMAT as you'll be very well versed in at least reading and writing sections.
Here's my score breakup FY reference-
My GMAT debrief: from-620-to-710-my-gmat-journey-114437.html