A clean car is a happy car, and it also reflects on you as an owner. Take pride in keeping your car clean inside and out, and people will notice. One step above just washing your car is getting it detailed. Detailing isn't just an interior cleaning, detailing can be an exterior concept as well; and you might be surprised what goes in to detailing a vehicle.
Detailing a car's interior means paying attention to all the cracks, crevices and fabrics inside your vehicle. An easy place to start is by removing the floor mats. Vacuum the mats, floor of the vehicle (front and back, moving the seats forward and back to reach all the carpet), upholstery, rear parcel shelf, dashboard and trunk.
If your carpet or upholstery has any stains, using a foam cleanser and rubbing it in with a damp cloth or sponge should get rid of them. Make sure you allow the cleanser to set in for a few minutes before scrubbing the spot. Repeat as many times as needed to clean the spots. Make sure to wipe up the cleanser with a damp (not soaking wet) sponge and do a final blotting with a dry towel to get all the wetness from the fabric and carpet as possible.
Leaving your fabric and carpet damp may cause mold and mildew.
While your floor mats are out, spray them down to get all the sand and dirt off, and then dry them before putting them back in the car.
After you've cleaned the dash there are still probably places you can't easily get the dust out of. Using a can of compressed air should help blast that dust out of hard-to-reach places in the dash, doors, and other places around the car.
Wipe down all interior hard surfaces with an all-purpose cleaner. Use a super-absorbent (for dust) detailing brush on your air vent grilles.
For cloth seats, shampoo them with a wet-vac, making sure they are plenty dry afterward. Leather or vinyl seats can be cleaned with a special cleaner and wiped away with a microfiber cloth. Condition your cleaned leather seats so the leather looks shiny and doesn't dry out or crack.
Finally, spray glass cleaner on your interior windows and windshield and wipe off with a microfiber or lint-free cloth.