Continuity mistake: Right after Trey, Doughboy, Ricky, and Lil Chris have the football taken from them, they are walking away from the older guys. The guy who yells at his friend to give the kids the ball back, finally gets the ball and throws it back to Ricky. You will notice that when he throws the ball, he throws it as if Ricky was standing right in front of him (meaning with little or no effort), but as they cut to the scene where Ricky catches the ball, he is much, much further away, and the ball should never have reached him, yet it reaches him on a fly.
Continuity mistake: While standing next to Dough Boy's car at the Crenshaw hangout, Ricky's holding the Doritos bag with the back of the bag to his thumb. When Ferris slams his shoulder into Ricky and spins him around, the front of the bag is to his thumb. It flips back again in Ricky's reaction shot.
Continuity mistake: When Trey is taking Ricky to football practice in his car, Ricky walks up to the car and Trey's window is rolled down. Then when the camera shows Trey while the both of them are talking in the car, the window is rolled up. Then the window is down again when they drive away. It's hard to tell that the window is rolled up but if you look closely, you can see Trey's reflection in it.
Continuity mistake: When Furious is showing Tre and Ricky the billboard in Compton, there's a flat stick lying on the ground by their feet. In the shot with Furious alone, the stick lies half in / half out of the streetlamp's shadow. In the shot with all three actors, the stick lies completely outside of the lamp's shadow.
Continuity mistake: During the final scene where Doughboy is sitting on the front porch with Tre and talking, you can see most of the porch is in shade. When Sherryl walks onto the front lawn and starts talking to them, the sun is now shining brightly on her and on the front porch. This happens throughout the scene. All the wide shots of them on the porch, they have the sun shining brightly while all the close up shots of them talking are in the shade.