1) Only ever cheat when you have to. 

2) Only ever accuse someone of cheating if youre 100% sure theyve cheated. 
3) Dont give up! Even if you have 25 cards - carry on.                                

4) If you cheat, only play 2-3 cards - play 4, and youre guaranteed to get caught! 
5) If someones just played their last card, accuse them of cheating. If they werent cheating, youll lose anyway. But if they were - you stay in the game.