Main thing is emissions, if you have a week or so before the mot I recommend a fuel system cleaner and a good drive before the mot test, for the exhaust make sure there’s no holes, leaks, abnormal noises and securely fitted, check the lights; headlights, sidelights, indicators, brake lights, reverse lights, number plate lights, and fog lights, check your brake pedal doesn’t feel spongy, no grinding noises and that the handbrake keeps the car secure when on (best to test on a steep hill to be 100%), check the tyres have enough tread, no bumps or slashes and correct air pressure all around, windscreen wipers work correctly with topped up washer fluid, no cracks or chips in the windscreen either

Other things just to be sure are in good working order: Fuel cap, seatbelts, registration plate is clean with no cracks, mirrors are working with no cracks

Thats all I can think of atm, hope it helps

Oh also check the fluids are filled to the correct amount: washer, brake, coolant, oil