Hi maliyeci,
my experience says that TOEFL questions are like a children game in comparison with GMAT ones...
Take into account that the TOEFL ibt exam tries to measure your english level, however, GMAT exam tries to measure much more of your skills.
I'm pretty sure that if you practice for the GMAT's writing section (AWA), you'll not find problems in that of TOEFL
Regarding speaking section... mate, this is the most difficult one. My two cents on this point:
· Try to be the first person to enter the class. At least in my case, people started the exam as they entered the class, so, people were at different parts of the exam when I was starting it. Imagine doing the listening section while other people is doing the speaking section...
· Practice in answering all the questions you're asked in the speaking section, and don't worry if there are a few seconds left when you finished your question.
All the best friend