first all of all never become Demotivated ... If someone demotivating u then u just smile and say it back thank You so much for Encouraging me bcoz that positive word from ur mouth can shut the other person's negative effects.. Be positive always and think about yourself that " I can do anything Nothing Is Impossible for me. I have crossed many stages of my life and came here This is not so easy for me ".
and If i talk about the preparation then for that u have to do lot of practise in dialy routine. make ur time table that covers ur all topics.