Does anyone know any good sites for TOEFL and GRE preparation
For TOEFL I downloaded Cambridge and Kaplan tests, solved them twice and I got 84 (R:20, L:22, S:20, W:22). But I suggest you to listen youtubers to learn daily conversations, phrases and implications especially for listening and speaking sections.
TOEFL level English is not that hard but the exam itself is physically tiring. It's really hard to stay focused.
I am also doing some Ph.D. applications. Generally 80 is sufficient for non-English speaking countries but for US and Canada requirement is generally 90 for top universities with at least 20 for each section.