As you have used two power source you must common ground them.
**You must check L298N motor drivers enable pins.As you have only 4 wire to motor driver from arduino.So you must give EnA and EnB pin 5v/HIGH or You can give it (0-255) pwm value from arduino to control the speed of your motor **
If wiring is ok then you must go throw you Sketch....
I don't know your motor-driver board but here are several things to check out, based on your schematic:
The motor driver board has two enable pins. Neither of them is connected. It would make sense that these pins turn the two motors on and off.
The pin marked 12v is connected to +5v.
The linked photo of your car shows two 9v "Transistor" batteries. This ...
The ENA/ENB (enable A/B) pins have to be at HIGH level (either hardwired or set by an mcu). There exist lots of different driver boards (mostly based on the same ICs) which sometimes don't provide this enable pin, but they are "enabled" by default. You didn't tell us which board you use, but you'll know.
Since you seem to need some orientation, I will explain a few things, to get you started.
The MPU6050 is a device, that communicates through the I2C interface. It uses 2 communication lines (SCL for the clock and SDA for the data). To use is with the Lilypad, you have to connect those two lines, Vcc (5V) and Ground. If you look at a pinout diagram, you can ...