To be prepared for any entrance exam, one must need to practice previous years' exam papers, solve sample and give mock tests as much as possible. NTA has released model papers, which you can download from the given link-
http://engineering.careers360.com/articles/jee-main-sample-papers
Jee Main is almost knocking at the door, so boost your preparation with our unlimited mock test series, video lectures, smart study material etc.
Go through the link, for more details about the mock tests series-
http://learn.careers360.com/knockoutfull-jee-main-january/?jee-main-knockout-lpage&ici=JEE_Main_text-mapping