You can prepare online from http://accelerategateelect.vriti.com/
Many features like the below mentioned are imbibed here which can help a GATE aspirant to assess the overall performance

Previous year Solved Paper
Model Papers
Accelerate Score Predictor
Question Bank
Unit Tests
Comparison with Toppers, Your historical assessment
Syllabus, Unit wise breakup of the Exam, Syllabus Meter
Study Material
Doubt clearing Sessions