hi,

see you should take preparation by using previous years gate papers and the questions booklet available in market as per subject wise.

gate XE questions paper pattern is as follows:

First section is General Aptitude

Second section is Engineering Mathematics

The third part comprises sections of B to H and candidates have to select  any two sections to write gate exam.

now you will get various study books from made easy, gate academy, ace academy where ample questions is available for aptitude and mathematics  preparation.

you may follow gradeup mock test series for gate XE papers. apart from this try to revise the syllabus from text books and make short notes for revision purpose.