If you do not get pharaoh by scratching his head, throat or back goto your item section and give him a sandwich, he will now follow you

As the title says, there is an easy way to get good DP. First of all, you should start this in 2nd May after school. Then go outside and duel first Gillian once. Then go and fight duelists like Damon, Syrus Truesdale, Nova or even your teacher Vellian Crowler. Duelist Bonus that you will get from these are like 150 and up. Try Nova ( obelisk blue boy ) then the others. In one day you should accumulate like minimum of 20,000 if you managed to duel them 2x before you save.

Here is an easy way to get lots of DP without wasting your time before the tournament, load up your data and then go to free duel, select tag duel and choose your partner, then do a match duel. After the match duel you get DP and when you go into story mode the DP is there and you haven't lost any time.