TOEFL

Hi,
I can talk for IELTS. In my opinion, give it a good 3 months preparation time. Do a regular practice and be consistent. You can actually clear on your own.
1. Enroll in a lot of free courses online like on future learn. There are so many websites like IELTS buddy, IELTS advantage, IELTS Liz etc. to get tips and tricks. There are you tube videos too for visual demonstration.
2. Get Barron's and Official IELTS Cambridge books, I personally think they are very good. Follow them regularly and solve all papers.

Yes, you can apply. While processing, the score is valid. They will consider. You cannot apply after 13th August.

Hi,
Some popular ones are mentioned below:
For GRE follow ETS: GRE The Official Guide to the Revised General Test, Kaplan's GRE Premier and Barron's GRE. A number of practice tests are available online. For TOEFL : Official Guide To The TOEFL by ETS, Cambridge Preparation for the TOEFL Test etc. For IELTS The Official Cambridge Guide to IELTS Official IELTS Practice Materials (1 and 2) by British Council
Cambridge ESOL
IDP: IELTS Australia and so on.

TOEFL is mostly preferred in USA and Canada and IELTS in European countries. If you are comfortable with American English then take TOEFL and if you are comfortable with British English then take IELTS. Also, check university requirements.

In America, TOEFL is a good exam. The USA has its own criteria for selecting the student. Some countries take students without GRE, but in America many colleges prefer GRE, so if you really want to study in the USA, go through TOEFL and as for scholarship, I will suggest you to focus on the admission now.

It depends on the university and the country in which you are going. Some ask for both the scores, some only require SAT and an English language eligibility test.

Magoosh Online GRE Prep is one of the best online tools available for GRE coaching. It is complete online programme with vocabulary building, Practice tests (sectional and complete). Each and every question is explained well via video tutorial and also offer email support.

Best place is the official website of the universities to which you want to apply. Read the information given on it about admission, scholarship, and application. Where you want to study and when?

It is absolutely important to give such exams. It is to determine your English communication skills. It is important because you will have to live in a different country so you must be fluent in English and these tests check your ability.

Yes, you are eligible for scholarship, but universities will assess your profile and then they will give you a scholarship.