I have some advice for you:
#1- Try to think of the bright side of life. Stay positive, and feel that the glass is half full instead of half empty.
#2- They’re kids, you’re a kid (not trying to be offensive), so try to find common ground with someone, or use the fact that they’re also a kid to your advantage.
#3- If they draw on your paper, draw a smiley face on theirs. It may get you in trouble or may make the opponent try to draw on your papers more, but that’s their choice. If they’re choosing to be brain-cell-less, that’s something that you may have little or no control of.
#4- Any other forms of Annoyance, Bullying, or Complications (I call that the ABC) with anyone else, or the same people for different reasons, my best advice would be to talk to an adult, like school staff, trusted adults/guardians, or your parents (this includes your grandparents).