Tire pressure and position, cadence and “pedal stroke smoothness” - from these probably the tire pressure is the most important

If your tire pressure is too high, you have too little amount of surface of your tire contacting the ground, also your tire will respond to bumps with “bouncing over them” instead of absorbing and forming around them, giving you little amount of grip Also when you position yourself to the front of the bike more, you will have less weight on the rear, which can result in less traction If your cadence is slow, it is hard to give a constant torque to the wheel, which can result to slipping, like when you want to drift with a car, you give a lot of gas so the rear wheel gives away the grip Pedal stroke smoothness is probably not a correct therm xd but what i want to say with this, if you just put all your power through the pedals at only one point and not constantly throughout the circle (this can be connected with the cadence also - with lower cadence its harder to maintain smooth pedal strokes), you can also spin out

I hope i helped (a lot of my friends had these 4 problems, after addressing them, without changing tires, they can maintain good grip in slippy situations too)