by good preparation and analyse yourself in which categories of test you are weak......lik english, Math, Analytical..........I have got 49 in my 1st attempt...at that time i think analytical is the major portion in which i am much weak......than i started preparing it and got 65 marks and improved analytical portion form 15 marks to 30 Marks....than i think that i am weak in Maths and i was standing at 18 marks in maths.......I have prepared math from different GRE books and also downloaded some topics from Youtube in which i think i was weak......and in the last attempted test i have got 76 total and in math portion i have got 29/30
i have got this much score by self study not got any tuition from any academy or person.