The first link below is for previous year GATE/TIFR questions (2478) mostly ordered year wise. It contains only questions and the second link contains corresponding question as well as answer(s).
You can download both and use the first one for taking practice tests. Solve every 65 questions and see how many you get correctly. To be really safe, you must be getting about 50/65 questions correct. 40-50 questions are also good. Below that you should see which topics are causing you less marks and prepare them further.
The below link is also for same set of questions but shuffled randomly. Might be useful for practice.