GATE

First of all, I don't know what is your department. So, I cannot tell you subject wise strategy. It is very difficult to prepare for GATE within 7 months, if you didn't study well during your previous semester. But, it is not Impossible. So going through basic strategy
Make detailed syllabus and sort out the subjects that you know well.
First of all, finish those subjects that you are interested in. You have 1011 Subjects appox. including engineering maths. Make a detail time table and divide all the subjects within 7 months. If you are finding any subject very hard to understand then you can skip 1 or 2 subject. Its is not an bad idea because time is too short. Don't Skip Engineering Mathematics. It cover 15% of total GATE marks. You can make weekly target and give revision at the end of the week
You can study 34 subject at once. At the end of the day you know your strength and weekness very well. Prepare a routine accordingly and follow them.
Best of luck.

Solve at-least last 10 years Previous Papers. It will make you get the idea about the type of Questions being asked in the Exam. Focus more on 2 mark questions. They boost your Score exponentially.
Practice as many Mock-tests as you can (that too as per the Standard pattern of the GATE Exam).
Keep your fundamentals and concepts clear. The Questions asked in the GATE Exam are mostly based on the fundamental concepts. By giving these you will actually know about question pattern and gain experience for giving objective kind of test and also you will be able to measure your standard as per other student so that you can change yourself better to crack the exam.