Before stating the process of wiping the car with the wash medium it’s best to remove as much dirt and dust as possible with a rinse and, if possible, a pre-wash. When rinsing the car it is advisable to try and blast off dirt and grime at acute angles so as not to hammer the particles against the paint but rather propel them off.
It is best practice to rinse the car with a hose to remove the obvious dirt. Personally I use a pressure washer for this stage and I find the results have been much better, however they are far from essential as long as you have a hose. I currently use a Karacher pressure washer but it doesn’t need to be an expensive one.
As noted I consider a pressure washer a luxury item for cleaning the car, I would not be concerned if you did not have access to one but they can be quite useful if you have some spare cash or vouchers to use up! Do not feel disheartened if not though.
Pre-washing to me is defined by washing the car as far as possible without every actually touching it. One of the most popular ways to do this is by using a foam lance with appropriate mixture to cover the car. What this does is propel foam over the car which then clings to the outside. The suds sit on the car penetrating into the dirt and then, when you wash off after a while (usually three to five minutes) a considerable chunk of dirt comes away as part of the rinse. A foam lance usually requires a power washer to operate and the lance will need to be the correct fitment for the power washer.
A foam lance that attaches to a hosepipe directly is available and comes highly recommended by other detailing sites. I personally have not used it, however.
I am currently using Meguiars Hyperwash which is a fairly gentle, multi-purpose detergent. This is useful as it preserves my wax layers from previous cleans (see later) while still taking off the dirt. If the car is dirtier a stronger mix can be used. One suggestion is to combine Meguiars Hyperwash with a part mix of Meguiars Multi Purpose Cleaner.
When using a foam lance I fill it up with 150ml foam and 850ml water. You then attach the lance to the power washer and apply liberally all over the car from three to five feet away working from the top of the car to the bottom.
After about five minutes (in this time I often prepare the next step of my wash by getting my buckets ready) I rinse the car with the power washer thoroughly until no more suds come off of the car. Take particular care around the body seams that can trap dirt and soap.
Please also be careful not to fire the hose or pressure washer directly off the ground as this can spurt dirt up onto the car!